be happy that 中that引导的是原因状语从句，说明高兴的原因，相当于because引导的句子.“be+形容词+that从句”是英语的表达方式之一，例如：lam very happy that you could visit us."您能来拜访我们，我们很高兴".再例如:He was glad that he had made great progress in hisstudy."他很高兴自己...