不知怎么地,他在解这道数学题时又算错了.Somehow he again made a mistake in solving the mathematical problem.服务员算错了账.The waiter got his arithmetic wrong.账算错了, 少一块钱.This account is wrong; we're one yuan short....
There are telephone extensions in every room.每个房间都有电话分机.Some of the best extensions are made from sections of rod tube or drainpipe.最好的延长管中有些是用杆管或排水管制成的。There are telephone extensions in every office.每间办公室都有电话分机....