他们听到这个消息很高兴（中译英）是They are very happy when they heard this news还是They were very happy when they heard this news还是They are very happy when they hear this news.从句的时态,是否与主句的时态相同?还是不同,这句话用不用过去式
问题描述：
他们听到这个消息很高兴（中译英）
是They are very happy when they heard this news还是They were very happy when they heard this news还是They are very happy when they hear this news.从句的时态,是否与主句的时态相同?还是不同,这句话用不用过去式
答