Teachers have to constantly update their knowledge in order to maintain their professional ________．
A．consequence B．independence
C．competence D．intelligence
—China is developing rapidly.
—Yes, to make our country more prosperous, we should firmly the principle of scientific development.
A. contribute to B. subscribe to C. stick to D. turn to
Saving and recycling are long-term projects _______ determination matters a great deal.
A. that B. which C. whose D. where
Jack wasn’t saying anything，but the teacher smiled at him ________he had done something very clever．
A．as if B．in case
C．while D．though
US President Barack Obama ________ a national speech at the 10th anniversary of 9/11 terror attacks．
A．addressed B．delivered
C．spoke D．recited
Mistakes don’t just happen; they occur for a reason. Find out the reason, and then making the mistake becomes ______.
A. favorable B. precious C. essential D. worthwhile
