侠客行中的石破天，是（）的儿子。
参考答案：石清和闵柔
Mr Li wants to buy a chair and a desk, so he has to go to a __________
a. drugstore b. furniture store
c. sports store d. bookstore
风蚀强度分级按( )三项指标划分。
A．植被覆盖度(%) B．生物量C．年风蚀厚度(mm) D．侵蚀模数[t/(km2·a)]
