China ______ the WTO for more than 10 years, and it has brought great changes to it.
I think ______ is necessary ______ us to do something useful to protect the birds.
Dick ___________in America, but now he has been_______Chinese food since he moved to Wuxi.
The words that we should pay attention to ___________ on the blackboard.
The work is too difficult for Mr Zhu to finish in a week. He needs ___________ days.
Daniel is very modest. He never ___________ before his friends.