Question

i began to learn dancing at the age of four

At the age of four，she began to learn dancing．（改写成复合句）
She began to learn dancing______was four．

Answer 1

答案：when she第一句中“at the age of…在…岁时”可以转换成when引导的时间状语从句，第二句考查时间状语从句，当…的时候when，主语为she，故填：when she．