局部通风机进风口前后（）范围内不得有杂物、障碍物或密闭。
A、2m
B、4m
C、5m
D、6m
参考答案：A
已知全集U=R，M={x|-2≤x≤2}，N={x|x＜1}，那么M∩N=（ ）
A．{x|x＜1}
B．{x|-2＜x＜1}
C．{x|x＜-2}
D．{x|-2≤x＜1}
Many parents prefer kindergartens to spend more time teaching math and Chinese to help their kids _______ an early lead in primary school performance.
A．bring up
B．take up
C．build up
D．add up
