Jenny ______________ on the couch now.[ ]
A. sit
B. sits
C. is sitting
D. is siting
答案:C
Running is and safer than skiing. [ ]
A. cheap
B. cheaper
C. popular
D. difficult
通常用的钢丝绳卡子有()。
A、骑马式
B、压板式
C、拳握式
D、背复式