胎儿已成熟,吸吮力强的时间是()
A.妊娠16周
B.妊娠20周
C.妊娠28周
D.妊娠36周
E.妊娠40周
参考答案:E
You'd better _____ for school again. [ ]
A. not be late
B. not to be late
C. be not late
D. to not be late
分类汇总前必须对要分类的项目进行排序。