- areto怎么这么用ThosewhowanttogotoTibe
- The who want to go to Tibet are to sign their names here.
are to 翻译为必须，须
be to 是一个词组吗？ 还是接的动词不定式
- be to 等于一个动词不定时短语。
例如：
You are to understand the meaning of "Those who want to go to Tibet are to sign their names here." I am to explain it.