The teachers_________(sing)in the office now.

The teachers_________(sing)in the office now. Listen!A girl ( )(sing) in the office now. Is Mr wang in the office now? they()in the classroom now A sing B are singing I heard the birds____(sing)in the forest just now 请问这里用sing I think he must be in the office now,______? my teachers are having a metting in the office now My teachers ____(not be)in the office now _ Jim andMichael()in the teachers' office just now listen Tom is sing .that _____be Tom .he is in the office A. I found him in the office.A.sing B.sings C.was singing working in the office