根据煤炭部新的分类标准，含煤岩系沉积岩分为：（）和（）两大类。
参考答案：它生沉积岩；自生沉积岩
已知集合A={x|x2-x-2＜0}，B是函数y=lg（1-x2）的定义域，则（ ）
A．A=B
B．A⊊B
C．B⊊A
D．A∩B=∅
If city noises ______ from increasing, people______ shout to be heard even at the dinner table 20 years from now. (MET1992 )
A．are not kept; will have to
B．are not kept; have to
C．do not keep; will have to
D．do not keep; have to
