If the skirt is ____ ___ , I’ll take it.

The computer system _____ suddenly while he wassearching for information on the Internet.

_____ some knowledge of cooking just by watching my mother doing it.

―Where’s your father―He _____ abroad on business.―Really But he can’t _____ many English words.

We have done things we ought not to have done and ______ undone things we ought to have done