如果ab>0,a + b<0,那么a、b的符号分别是( )
A.a<0,b<0
B.a>0,b<0
C.a>0,b>0
D.a<0,b>0
答案:A
解:,同号,
,,
故选A.
根据句意将括号中的字母组成正确的单词并填空。
1.(seerar) A: Is this an ?
B: No, it isn't. It's a pencil sharpener.
2.(pesll) A: How do you pen?
B: P-E-N, pen.
3.(htta) A: What's ?
B: It's a book.
4.(kacpback) A: Is that your ?
B: Yes, it is.
5.(Enligsh) A: What's this in ?
B. It's a telephone.
学龄期是智力发育的关键时期。