问题描述：
signal的近义词?
She wondered how she could send a signal.She wanted to send _.
a.a letter
b.a sign
c.a signature
d.a message
She wondered how she could send a signal.She wanted to send _.
a.a letter
b.a sign
c.a signature
d.a message
问题解答：
我来补答展开全文阅读