港内停泊船含油量小于15ppm的污水（）排放。
A、禁止
B、可以
C、酌情
D、视情况
参考答案：A
函数f(x)＝x3＋sin x＋1(x∈R)若f(a)＝2，则f(－a)的值为 ( )．
A．3
B．0
C．－1
D．－2
Our teacher said there would be ______ books in the new library.
A．thousand
B．thousands
C．thousands of
D．thousand of
