The problem is so complex that I'm afraid it will take me several hours to________.
It is the protection for the trees___________ really matters, rather than how many trees are planted.
We can’t go on with the experiment because the computer_________.
The two sides have finally___________, though some small differences still exist.
He has a part - time job and was paid___________.
The sunlight came in____________ the windows in the roof and lit up the whole room.