A：
B：
C：
D：
与土壤保水、保肥、通气、透水能力有关的主要因素是（ ）
根据问句，选择合适的答句。
①Does Jane have a soccer ball?____ A. OK.
②Do you have a baseball bat?____ B. It's in my bedroom.
③Let's go!____ C. Yes, she does.
④Where's your baseball?____ D. No, I don't.
⑤Is it under the teacher's desk?____ E. Yes, it is.
51－19=____ 73＋25=____ 920－500=____
200＋800=____ 40＋600=____ 63÷9=____
互为同分异构体，遇氯化铁溶液显紫色的有机物是
