A:12
B:22
C:- 12
D:0
①氧气仅由一种元素组成,而水是由氢氧两种元素组成的纯净物;②氧气是纯净物,水是混合物;③氧气是由同种分子构成的,水是由氢、氧两种分子构成的;④氧气分子是由同种原子构成的,水分子是由不同种原子构成的.
一个多边形的外角和是内角和的一半,则它是( )边形。
根据短文内容和所给的汉语提示,写出短文空白处各单词的正确形式,每空限填一词。Miss White is from France. She can speak two____ (语言). She is a ____ (护士). She works in a ____ (医院)at night. She works very____ (努力). She likes to take a walk in a ____ (安静的) place. She likes ____ (动物) . She often goes to the zoo. Her cousin Bob is a reporter. He’s ____ (拍照)photos at the park . It’s____ (寒冷的) today. Look! Some people are swimming at the____ (泳池). Mr White is____ (感到惊讶的)to see it.