练习者以右腿做跑动挂膝上，帮助者应站在（）。
A、杠前左侧
B、杠后左侧
C、杠前右侧
D、杠后右侧
参考答案：A
Five _______ students from different schools took part in the English contest last Saturday. [ ]
A. hundred of
B. hundred
C. hundreds of
D. hundreds
天疱疮是结缔组织疾病之一。
