GreatasNewtonwas,manyofhisideas____todayandarebeingmodifiedbytheworkofscientistsofourtime.
A、aretochallengeC
【句意】尽管牛顿非常伟大，然而他的许多观点当前正受到怀疑，并且当今的许多科学家正在努力对这些观点进行修正。
【难点】challenge意为“挑战，怀疑”，常用作及物动词。本句中牛顿的观点受到挑战为一个当前已经发生的事实，故采用现在完成时的被动语态。
Thecaris_____expensive_____hecan’tbuyit.
It’s necessary ______ us to keep our pets clean everyday.
I ’d like to have a long holiday, but I’m really too busy to _____ the time.
I hope my father____ ask me about my marks.
___ will Mr. Forbes be able to regain control of the company.
