Does 都 refers to the 天天 or to the 晚上 in the following sentence? Does 都 refers to the 天天 or to the 晚上 in the following sentence:


  天天晚上都很忙
天天晚上 is a single set phrase meaning every night.

都 refers to it [each evening].

Thus we have: [I'm] very busy every night.