Mr． Wang， must I come back to clean the classroom again？
No， you_____． I have asked Kate to do it．（ ）
A．mustn'tB．needn'tC．shouldn't
We've got everything ready for the picnic．
Do you mean I ______bring anything with me？（ ）
A．can'tB．mustn'tC．couldn'tD．needn't
Could you help me with housework _____you are free today？（ ）
A．sinceB．thoughC．unlessD．until
_____do your parents take exercise，William？
Less than three times a week．（ ）
A．How longB．How muchC．How soonD．How often
Tom wants to study at ______university in Europe，but hasn't decided which one to go to yet．（ ）
A．anB．aC．theD．不填
Could you tell me ？
Every four years．The 24th will take place in China in 2022．（ ）
A．how long the Winter Olympic Games last
B．how long do the Winter Olympic Games last
C．how often are the Winter Olympic Games held
D．how often the Winter Olympic Games are held