John knocked at the door for nearly five minutes____his wife opened it.
The flowers will die soon unless often ________.
The report shows that we’re making some progress but ______ we need to make greater efforts.
A good idea ______me! Which of the following is Not Right?
A number of tests have been conducted to _________ that these drugs have no side effects.
---Why did Tom become wealthy this year?---Because he sold _________________ he did last year.