问题
选择题
There is ______ "s" and ______ "u" in the word "supper". [ ]
A. a , a
B. a, an
C. an , an
D. an, a
答案
答案：D
搜题请搜索小程序“爱下问搜题”
There is ______ "s" and ______ "u" in the word "supper". [ ]
A. a , a
B. a, an
C. an , an
D. an, a
答案：D
“v—t”图象下的“面
x；加速度的定义为
则“a—t”图象下面的“面积”在数