题目内容：
Theexampleofthechildrenholdinghandswhencrossingthestreetinthelastparagraphshowsthat__________. A．socialdistanceisnotalwaysneeded
B．thereisnosocialdistanceamongsmallchildren
C．humansaredifferentfromanimalsinsocialdistance
D．socialdistanceissometimesdeterminedbyoutsidefactors
参考答案：
答案解析：