初孕妇自觉胎动，多数开始于：
A．妊娠14～16周
B．妊娠16～18周
C．妊娠18～20周
D．妊娠20～22周
E．妊娠22～24周
参考答案：C
四冲程发动机曲轴转两圈，活塞在气缸内往复行程四次。
Every time_____they met, they would talk several hours together about all of the situations_____ appear in the working world.
A．that; when
B．when; where
C．which;what
D．/; that
