A：①②
B：①③
C：③④
D：②④
组别
亲代
F1表现型
F1自交所得F2的表现型及比例
实验一
甲×乙
全为产黑色种子植株
产黑色种子植株：产黄色种子植株=3：1
实验二
乙×丙
全为产黄色种子植株
产黑色种子植株：产黄色种子植株=3：13
In the future I am going to be an inventor．This winter holiday I don't want to go out to play．I want to ____something myself at home．I want to help old people____a light and folding bike．They ride it to the ____，then folding it and put it in the bag．After buying some things they can ride it and carry their things to go ____．They are not tired．I think if they see it，they must be very ____．
