— Many kinds of animals are in danger now.
一 That's true. And the government is making laws to protect them.
A:keep……clean
B:keep……safe
C:make……die
KCl与KNO3在不同温度的溶解度数据如表.则下列说法正确的是( )
温度/℃
10
20
30
40
50
KCl
30g
33g
35g
38g
41g
KNO3
21g
31g
45g
65g
88g
买一个足球需要m元,买一个篮球需要n元,则买4个足球、7个篮球共需要( )