It __________ be the vocabulary that caused you the problem in the exercise because you know a lot of words.
—Does he know how to work out the problem?---Yes, he has ___ a good idea to solve it. ----Yes, he has ___ a good idea to solve it.
---Excuse me,but I want to ride your bike to go to the bookshop. ---You ____ have my bike if you don't take care of it.
—Did your uncle phone you again the next day? ---No, it was a fortnight ___ he gave me a second call.
He has made another wonderful discovery,___ of great importance to science.
—Minister, are you satified with the performance of the Chinese athletes in Beijing Olympics? ---Yes, it couldn't have been _____.