Hadelectroniccomputersnotbeeninvented,__(很多关于太空飞行的问题不能解决了).
What can you do if you are not sure about the postage?
Ask ______.
Service contract is a part of the deal.
My father (read) __ your thesis all the afternoon.
You should avoid (meet) __ her in the street.
In the traditional usage, sports refer to __ activities.