Our foreign trade has________greatly in recent years .

A lot of children never fully ______ their mothers until it is too late.

Experts and teachers all think that failure is not _____ a bad thing to some extent.

(2013·安徽高考)________ in the early 20th century, the school keeps on inspiring children's love of art.

Peter had lost his job, and the family was ________ a very difficult time.