My father often reads a book before _____(go) to bed.

问题描述:

My father often reads a book before _____(go) to bed.

going

going 因为before是介词,后面要加名词或者相当于名词的词

going
before he goes to bed == before going to bed

你好;
填 going
before是介词, 所以它后面接 动词的 ing 形式