三代以内的直系血亲结合成夫妇,后代有可能出现的是( )
A:一定会得遗传疾病
B:不会得遗传疾病
C:得遗传疾病的可能性大大增加
D:A和B
v表示速度,t表示时间,s表示路程.
s=____,v=____,t=____
当a≥0时, a2 、 -a2 、 -a2 ,比较他们的结果,下面四个选项中正确的是( )
⑴made____ Look at that robot.
⑵strong____ My brother is hardworking.
⑶finish____ We can do our homework after dinner.
⑷girl____ My father helps him to clean his room.
⑸beautiful____ Li Hua is really clever.