The secretary has a lot of things to ________ in the office since she has been away for quite a few days.
He spoke so slowly that we all could ___ him.
I ___in North China, but now I ___ the weather in South China.
I have no idea __ the Greens has moved to Hangzhou or not.
---Is he here now?---No, I ___ he ___ here by now.
My brother tried ___, but still he couldn't work out this maths problem.