e the students understand the problemthe teacher tried to explain it, but the explanation just did not _________tothe class．

It will be many years ______ the doctors and medical scientists can find _____ for cancer

Peter and I ______ good friends. _______ are in the same school.

Sometimes Mr. Wang walked the restaurant and went into the coffee shop.

We all want to know ____ the famous writer will come to our school or not.