The boss believed Tom's reason for being late for work is ______ he had to help his grandma coo

题目简介

The boss believed Tom's reason for being late for work is ______ he had to help his grandma cook.

A．why

B．that

C．where

D．because he

题型：单选题难度：中档来源：不详

考查表语从句。That he had to help his grandma cook是一个表语从句，这个句中结构很完整，that只起引导作用，不充当任何成分。