把……变成________

把……变成

把下列句子合并成含有定语从句的复合句，每空一词，使意思基本不变．

Do you know the boy? We met him in the hospital.

Do you know the boy ________ ________ ________ in the hospital?

把下列句子合并成含有定语从句的复合句，每空一词，使意思基本不变．

It's one of the most important meetings. Many meetings have been held this year.

It's one of the most important meetings ________ ________ ________ held this year.