—Bob, your room is so dirty. It must ________ every day.
—OK. Mom, I’ll do it right now.
clean
be cleaned
is cleaned
There is going to ________ a sports meeting next week. If it ________, we’ll have to cancel(取消)
---He has never spoken to a foreigner. ---________.
--I don’t know if his uncle ________. --- I think he ________ if it doesn’t rain .
The boy is afraid ________ cross the bridge, because he is afraid ________ falling into the river.
The writer found ________ difficult ________ English.