衰退行业中的竞争战略选择有观望战略、抽资转向战略、快速退出战略和（）。
A.差异化战略
B.领先战略
C.密集增长战略
D.市场渗透战略
参考答案：B
始祖鸟化石是______类进化成______类的证据．
Mary’s red face suggested that she_______shy, and her friends suggested that she______a deep breath.
A．be; should take
B．was, take
C．should be; took
D．was; takes
