一般认为，智力落后儿童的智商通常低于（）
A.40
B.50
C.70
D.90
参考答案：C
______ there’s going to ______ a basketball match tomorrow，______ I won’t go to watch it because I’m very busy.
A．Though; be; but
B．Though; have; /
C．/; have; but
D．Though; be; /
一种合金是由锌和铜制成的，它们的质量比是7∶3，这块合金重12克，含锌和铜各多少克？
