Helen and Bob are working hard these days because they will put ______ a short play in the school Talent(才艺) show.
A:over
B:away
C:off
D:on
某合作小组要探究“水分对鼠妇生活的影响”,提出了四种设计方案,其中最合理的是( )
下列透镜中,属于凹透镜的是( )
读下图,回答下列问题。
词语解释:
①拈花惹草
②示瑕求疵