________(occupy) with his work in the Satellite Launch Site, he could not spare any time to stay with his parents though they are very old.
Only after he had spent several nights working on the math problem _______ to wonder whether the problem was wrongly set.
__________ David could remember, he had never said an angry word to that customer.
________ enthusiasm when he heard our advice, he didn’t take any notice.
You must have waited here for a long time, __________?
Although a teenager, Fred could resist ______ what to do and what not to do.