Being a teacher always encouraging students to think for themselves, I won't tell them answers until they __________ on a math problem for more than an hour.

The order is that all the goods _____ to the city on time.

一You seem to be familiar with this city．一I_____ here for three years．It’s great to be back．

They became friends again that day. Until then, they _______ to each other for nearly two years.

—Who do you think will get the first prize?     —Mary, of course. She ________ for the competition for months.