A:y=3x
B:y=﹣2x﹣6
C:y=3x
D:y=12x2+3x+4
在Rt△ABC中,∠C=90°,有两边长分别为3和4,则sinA的值为____ .
阅读对话,判断句子理解的正误。
Xiao Qiang: Where is the school, John and Lucy?
John: Sorry! I don't know.
Lucy: There it is.
Xiao Qiang: Thanks. See you later.
John and Lucy: Goodbye.