Stronger than FM radio signals, these RF waves are still a billionth theintensity of known carcinogenic radiation like X-rays.本句中 a billionth theintensity 这几个单词连用,比较奇怪,billionth为什么后面直接可以跟名词呢?请教老师了,谢...
_______ did you beginto study French? I ________ to study French when I was seven.A. When, begin B. When, began C. While, beginning D. While, was beginning.这个选什么?为什么?能分析下吗?谢谢!