It is obvious how bad movies will impact ________ children.
A、onA
impact有时也可以当作一个动词来用，与之搭配的介词仍然是on。句意：坏电影对儿童会产生什么影响是显而易见的。
So far scientists have only acquired ________ understanding of the physical processes that cause earthquakes.
Therearemanysalesthisseason,duringwhichstoreswilllowertheir_______prices.
—Youwerebraveenoughtoraiseobjectionsatthemeeting.
—Well,nowIregret________that.
名词解释：silentpartnership
The traffic was held up for more than thirty minutes, ________ caused me to arrive late.
