A：
B：
C：
D：
根据短文理解，判断正误。
Tomorrow is Childre's Day. I want to buy some nice gifts for my children. Look! This green sweater is nice. I'll give(给) it to Anna. I'll give this pair of shoes to Peter. The pink boots are pretty. I'll give them to Mary. Oh! This hat is so colourful! It's forty yuan. I'll give it to Mini. This T-shirt is nice. It fits John well.
图甲是人类某遗传病的家系系谱，致病基因用A或a表示．分别提取家系中Ⅰ1、Ⅰ2和Ⅱ1的DNA，经过酶切、电泳等步骤，结果见图乙．以下说法正确的是（ ）
用所给词的适当形式填空
是等比数列，且
、
是
的两个零点，则
等于
