分析推理是化学学习中常用的思维方法．下列说法正确的是（　　）

儿童缺钙会出现（  ）

根据所给情景完成下列对话，每空一词。

A: Hi! Jack. Do you want to (1) ____ English with me?

B: Yes, I (2) ____ .

A: What (3) ____do you often go to school?

B: I often go to school (4) ____  seven o'clock.

A: Oh, it's quite early. I get (5)____at seven. I often go to school at 7:30.

B: My home (6) ____  near the school. Do you have lunch (7) ____ home?

A: No, I (8) ____ . I have lunch at school. After lunch I play basketball (9) ____my friends.

B: Great! I like playing basketball, (10) ____ . But I play it at 4:30 in the afternoon.

填空。

15－8＝____，12－8＝____，17－8＝____，16－8＝____

13－7＝____，11－7＝____，12－7＝____，16－7＝____