斜形砍击人体时，钝角缘挫伤明显。
参考答案：错
To keep healthy, Professor Johnson ______ cycling as a regular form of exercise after he retired.
A．took up
B．caught on
C．carried out
D．made for
下列哪些不是先天性心脏病病因（）
A.妊娠感染
B.遗传因素
C.缺氧
D.外伤
E.营养、药物及放射线
