Mary was very keen on the play.She went to the Grand Theater to watch it.(合并为一句）Mary was _____keen on the play______she went to the Grand Theater to watch it

so...that

so that
表示非常。。。以至于。。。
词句翻译为：玛丽如此喜爱这部戏剧以至于亲自跑到大剧院去看。

so
that

Mary was there keen on the play since she went to the Grand Theater to watch it.
自从Mary去大剧院看了它，就迷上了戏剧。