下列对加线词的用法，判断准确的一项是① 悦亲戚之情话，乐琴书以消忧 ② 彼于致福者，未数数然也 ③ 徐孺下陈蕃之榻 ④ 而后乃今将图南

You should move back and forth while _______basketball.

Can you _____ the meaning (意思) of the sign (标志)

I won’t share a bedroom you and I ’d like a room my own.

In that school, English is compulsory for all students, but French and Russian are ________. [ ]