单选题 The only thing ______ we need to think about is how to keep up with changes.

单选题 Before I go to the supermarket, I will make a list of ______ my kids need.

单选题 It was Lucy ______ helped me achieve my dream.

单选题 ______ he moved to this city, he has worked in the big company.

单选题 You ______ be careful when you use this camera, because it is very expensive.

单选题 My elder brother plays ______ basketball every week.

单选题 Cut the meat ______ a knife and divide it among four plates.

单选题 Computer software can be used to simulate the way ______ cells work.

单选题 ______ her telephone number and address, we couldn’t get in touch with her.