A:
B:
C:
D:
对甲地(25°S,175°E)的判断正确的是( )
填空
①That is not____kite.(I)
②The dress is____. Give(给) it to ____.(she)
③Is this____watch?(you) No,it's not____.(I)
④____is my brother.____name is Jack.(he)
⑤Here are many dolls,which one is ____(she).
如图是缩手反射实验示意图,根据图回答下面的问题.
已知{an}为等差数列,其公差为-2,且a7是a3与a9的等比中项,sn为{an}的前n项和,n∈N﹡,则S10的值为( )