Выберите правильные времена глагола:
a. have studied;
b. had studied;
c. am studying;
d. study; e. have been studying; f. had been studying; g. was studying

8. I … right now.
9. I … for two hours.
10. I … Chapter One.
11. I … Chapter One, before I began to study Chapter Two.
12. I … for hours, when Mother came.

a. have studied;

d. study;

8. I am studying right now.

9. I have been studying for two hours.

10. I was studying Chapter One.

11. I  had studied Chapter One, before I began to study Chapter Two.

12. I had been studying for hours, when Mother came.

Объяснение:

В 10 примере я указал длительное. Но, по сути из оставшихся вариантов можешь использовать любой. Т.к. временные маркеры не указаны.