What a hard life they _______!You should have helped him.[ ]

Once you _____ working with the professor, you will find he is not as tough as expected.

___________of last term we ___________ over two thousand new words.

I thought I knew the way to the small wood house in the jungle，but ________ I got lost

I hear Tom is good at ______, isn’t he— Are you joking Tom is weak at it. He doesn’t even know where Japan is.