The science of computer, _____rapid progress has been made in recent years, is the most important of all science.
At no time________the first to use the nuclear weapon.
__________ to sun, rain and wind for a long time, the stone split(裂开).
The arrangements for the English evening this weekend aren’t all_______;we needed another thirty chairs.
----Have the Smiths moved to California? -----Not yet, but they have ____________.
I have had such a case_________a boy whispered to his classmate now and then while I was having lessons.