______ she is sick or not, she is always happy. [ ]
A. Weather
B. Whether
C. If
答案:B
土中粗、细粒组含量相同时,土定名为( )。
A.粗粒土
B.细粒土
C.中粒土
D.以上均不对
胎儿在子宫中发育约需( )
A.280天
B.260天
C.240天
D.300天