Some aspects of a pilot’s job__________ be boring, and pilots often ________ work at inconvenient hours．
A．can; have to B．may; can C．have to; may D．ought to; must
The education system rather than the teachers __________for the overburden on the students．
A．are to answer B．is to answer C．are answered D．is answered
It is hoped that you can make some adjustments about the quality of your service the reactions of the customers.
A．in return for B．in response to C．in favor of D．in charge of
I broke my relationship with John because he always found_______ with whatever I did．
A．error B．mistake C．fault D．failure
Without proper lessons, you could ________a lot of bad habits when playing the piano．
A．break up B．pick up C．catch up D．give up
There are so many tall trees in the forest,______________.
A．some of them measures over 50 meters B．some of which measuring over 50 meters
C．some of them measuring over 50 meters D．some of which measures over 50 meters
