Question

→ Leia com atenção o exemplo sobre Abstract em Inglês Sublinhe ou destaque com outra cor as três sentenças no Present Perfect Tense:



Abstract Coronaviruses of human origin have emerged as probable important etiologic agents of acute upper respiratory tract illnesses in adults; their role in the etiology of respiratory illnesses of childhood is less certain. The first coronavirus of human origin, B814, was described in 1965 and since that time only 31 additional strains have been recovered. Ten of these were originally recovered in human embryonic tracheal organ culturesonly, and the remainder in monolayer cell cultures. All of the latter group were antigenically related to a prototype strain designated 229e. As a result of the fastidious growth requirements of these agents, most of the knowledge concerning the clinical syndromes associated with them has come from chajlenge studies in volunteers and seroepidemiologic investigations. Coronaviruses have been shown to be associated with a substantial number of adult respiratory illnesses especially during certain periods when rhinovirus infections are infrequent. Progress in propagating coronaviruses and in detecting coronavirus infections has been achieved recently: viruses similar to 229E were successfully recovered in human embryonic intestine cell cultures from patients with upper respiratory tract illnesses; 30C strains (B814, LP and EVS) were recovered in L132 cell cultures from infectious nasal washings; OC43(and OC38) viruses which were originally recovered in OC and later adapted to grow in suckling mice were not only shown to directly hemagglutinate various erythrocytes but were also adapted to grow in MK cell cultures; OC43 virus was also found to induce hemadsorption of rat and mouse erythrocytes in certain cell cultures; and a coronavirus strain was detected by immune electron microscopy. Coronaviruses are also associated with certain diseases in animals.

Answer 1

Resposta:

⇒⇒  Present perfect tense

Coronaviruses of human origin have emerged as probable important etiologic agents of acute upper respiratory tract illnesses in adults; their role in the etiology of respiratory illnesses of childhood is less certain. The first coronavirus of human origin, B814, was described in 1965 and since that time only 31 additional strains have been recovered. Ten of these were originally recovered in human embryonic tracheal organ culturesonly, and the remainder in monolayer cell cultures. All of the latter group were antigenically related to a prototype strain designated 229e. As a result of the fastidious growth requirements of these agents, most of the knowledge concerning the clinical syndromes associated with them has come from chajlenge studies in volunteers and seroepidemiologic investigations. Coronaviruses have been shown to be associated with a substantial number of adult respiratory illnesses especially during certain periods when rhinovirus infections are infrequent. Progress in propagating coronaviruses and in detecting coronavirus infections has been achieved recently: viruses similar to 229E were successfully recovered in human embryonic intestine cell cultures from patients with upper respiratory tract illnesses; 30C strains (B814, LP and EVS) were recovered in L132 cell cultures from infectious nasal washings; OC43(and OC38) viruses which were originally recovered in OC and later adapted to grow in suckling mice were not only shown to directly hemagglutinate various erythrocytes but were also adapted to grow in MK cell cultures; OC43 virus was also found to induce hemadsorption of rat and mouse erythrocytes in certain cell cultures; and a coronavirus strain was detected by immune electron microscopy. Coronaviruses are also associated with certain diseases in animals.

Explicação:

⇒⇒ Present Perfect >>> Indica quando a ação começou ou quanto tempo faz que ela está ocorrendo.

→→  situação/ação que começou no passado e continua no presente.

I have studied German since 2017. - Eu estudo alemão desde 2017.

(comecei a estudar alemão em 2017 e continuo estudando hoje)

→→  situação que aconteceu durante um período e que ainda não terminou.

Helen has been to the movies twice this week. (a semana ainda não

terminou).

→→  Uma ação terminada em um passado recente, confirmada pelo uso da palavra ''just''

David has just arrived from New York.  

∴  Present perfect - affirmative

Sujeito + has/have + verbo particípio + complemento

John          has                 played            soccer everyday.

They          have                lived               here for a long time.

She            has                  danced           since 2010.

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Answer 2

Resposta:

Coronaviruses of human origin have emerged as probable important etiologic agents of acute upper respiratory tract illnesses in adults; their role in the etiology of respiratory illnesses of childhood is less certain. The first coronavirus of human origin, B814, was described in 1965 and since that time only 31 additional strains have been recovered. Ten of these were originally recovered in human embryonic tracheal organ cultures only, and the remainder in monolayer cell cultures. All of the latter group were antigenically related to a prototype strain designated 229e. As a result of the fastidious growth requirements of these agents, most of the knowledge concerning the clinical syndromes associated with them has come from challenge studies in volunteers and sero epidemiologic investigations. Coronaviruses have been shown to be associated with a substantial number of adult respiratory illnesses especially during certain periods when rhinovirus infections are infrequent. Progress in propagating coronaviruses and in detecting coronavirus infections has been achieved recently: viruses similar to 229E were successfully recovered in human embryonic intestine cell cultures from patients with upper respiratory tract illnesses; 30C strains (B814, LP and EVS) were recovered in L132 cell cultures from infectious nasal washings; OC43(and OC38) viruses which were originally recovered in OC and later adapted to grow in suckling mice were not only shown to directly hemagglutinate various erythrocytes but were also adapted to grow in MK cell cultures; OC43 virus was also found to induce hemadsorption of rat and mouse erythrocytes in certain cell cultures; and a coronavirus strain was detected by immune electron microscopy. Coronaviruses are also associated with certain diseases in animals.

Explicação:

Presente perfeito = Has/have + (verbo no participio passado)

Significa que ocorreu no passado mais ainda tem efeito no presente.

Have emerged = have + ...ed

have been recovered e Have been shown = é mais complexo. È o presente perfeito da voz passiva. O BEEN ali no meio veio da voz passiva e esta ali extra.