下蹲控制姿势不变股四头肌的收缩形式是（）
A.等长收缩
B.等张收缩
C.离心收缩
D.向心性收缩
E.等动收缩
参考答案：C
It seems oil leaves from this pipe for some time. We'll have to take the machine apart to put it right.
A．had leaked
B．is leaking
C．leaked
D．has been leaking
明朝下列皇帝中，以藩王身份承帝位的( )P33
A．英宗朱祁镇
B．世宗朱厚熜
C．神宗朱翊钧
D．光宗朱常洛
