Circle the correct form of the verb. 1. we did not(know/knew)what to do. 2.The Russian visitors didn't (understood/untrstand)French . 3. We didn't (catch/caught) the baii. 4. The car didn't (started / start ) this morning. 5. The salesmen didn't (forgave/forgive) the thieves. 6. Recher didn't (felt / feel)well yesterday so she (leavers/ left)shool early. 7. She didn't 9choose/chose)the red sweater.

Так как во всех предложениях употреблен вспомогательный глагол прошедшего времени + частица "not", рассмотрим правило употребления с другими глаголами:

• После вспомогательных глаголов (did, does, do) главный глагол будет употребляться в начальной форме (настоящее время, но без частицы "to").

Поэтому получаем:

1. We did not know what to do.
2. The Russian visitors didn't understand French .
3. We didn't catch the ball.
4. The car didn't start this morning.
5. The salesmen didn't forgive the thieves.
6. Recher didn't feel well yesterday, so she left school early.
7. She didn't choose the red sweater.