Герундий или инфинитив

he must know a few of foreign languages. he must be working on his new novel now. perhaps they are enjoying the beautiful weather.

№1, стр.47.

1.her son is not an enjineer. he is a  scientist.

2.my father is not a fireman. he is a driver.

3.his grandmother is not a worker. she is a  pensioner.

4.liz and bob are not pupils. they are students.

№1,стр.54.

1.he is a officer.

2.she is a teacher.

3.they are doctors.

4.не is an officer.

5.they are enjineers.

преимущества и недостатки  современныхгаджетов.

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