We will go for a picnic if it 【doesn't rain】tomorrow.They (plan)a birthday party for Mr.Green at thr momentThey were planning a birthday party for Mr.Green at the moment.at the moment最好还是用过去进行时，比现在进行时更好。如果你们没有学过过去式，那就are planningWho (teach)them Chinese？Miss Gao.Who【teaches/is teaching】them Chinese？Miss Gao.teaches意思是每天教，is teaching意思是谁正在教