问题
选择题
Every day the mother seems to be busy until 10 o’clock at night, ____the rest of the family have fallen asleep.
A．that
B．by which time
C．on time
D．whose time
答案
B
根据从句的时态判断,所填词语必须含有“到……时候为止”的意思,并作从句的时间状语。that不可引导非限制性定语从句。on time意为“及时”,不符题意。D项错误,此题无所属关系。