专家为各位考生整理了雅思词汇每日一题：prior to供考生们参考使用。
Although the growth in Canada‘s population had slowed down by 1966 (the
increase the first half of the 1960’s was only nine percent) , another large
population wave was coming over the horizon. It would be composed of the
children who were born during the period of the high birth rate prior to
1957.
The phrase “prior to” is closest in meaning to which of following?
(A) behind
(B) since
(C) during
(D) preceding
