Uncle Wang is_____ the barber’s at the moment, so you have to talk to him _____ the phone.

When he walks ______ my desk, he often knocks my books off the desk. 

—The charity walk begins _______ 9.00 a.m. Don’t be late. —No problem.

Don’t get stressed _____. It will make you sick.

We couldn’t see the road clearly  _______ the heavy snow.