29It is required in a recent study suggesting the importance of teenagers’ communication with other children of the same age

How much ______ the socks—Two dollars.

The expert advised the boy, who always fails to remember the new words, to __________ an effective way of learning vocabulary. [ ]

to __ to the south, so now, I amused to __ in a hot climate.

I don’t remember how many years ago_____people began to grow crops. [ ]