Complete the sentences with the active or passive form of the verbs in parentheses.
Meat (must + keep)
in a refrigerator or it will spoil.
You (must + keep)
meat in a refrigerator or it will spoil.
It's painted
We're trying, but the window (can't + open)
shut.
I'm trying, but I can't + open)
the window.
The class for next semester is too large. It (ought to + divided)
in half, but there's not enough money in the budget to
hire another teacher.
Last semester's class was too large It (ought to + divided)
in half.
to the library by
These books (have to + return)
tomorrow.