He bought a house for his children ________
B
本题属于动词不定式复合结构做后置定语。in不可省略。句意：他买了一套房子给孩子们住。
TheFrenchmaintaina________separationofpersonalandprofessionallife.
Thechallengeisnotoneofexpansion._______,therapidgrowthinenrollmentoverthelast40yearshascometoanend.
Therearemanysalesthisseason,duringwhichstoreswilllowertheir_______prices.
—Youwerebraveenoughtoraiseobjectionsatthemeeting.
—Well,nowIregret________that.