容重越小,孔隙度越大,土壤通气透水性却不一定较强。
参考答案:对
用所给单词的适当形式填空。
l. Jenny begins____ (make) cookies.
2. This cookie is____ (you), Jenny.
3. I want you____ (remember) China.
4. "It's a good kite!" says Danny (happy).
5.There are twenty-four____ (hour) in a day.
在一个种群中若基因型为AA的个体占30%,则群体中A基因的频率一定是0.3%。