单选题 平面内有10个点,且任何3个点都不在一条直线上,以每3个点画一个三角形,一共可以画( )个三角形.
120
720
30
13
单选题 I regret ______ you that your application has been refused.
inform
being informed
to be informed
to inform
单选题 I remember ______ to the zoo by my father when I was little.
being taken
taking
have been taken
to have taken
单选题 The drowning boy made a ______ attempt to catch the rope thrown to him.
dangerous
graceful
gentle
desperate
单选题 若 ,给出下列不等式: 其中正确的不等式是( ).
①④
②③
①③
②④
单选题 关于实验室制备乙烯的实验,下列说法正确的是( ).
反应物是乙醇和过量的3mol/L硫酸的混合液
温度计插入反应溶液液面以下,以便控制温度在140℃
反应容器(烧瓶)中应加入少许瓷片
反应完毕先灭火再从水中取出导管