题干
You'd better ________ upstairs and tell the children not to make so much noise.
A：going
B：to go
C：go
D：went
答案(点此获取答案解析）
C
You'd better ________ upstairs and tell the children not to make so much noise.
A：going
B：to go
C：go
D：went
，则边BC的长为（ ）