白藜芦醇( C 14 H 12 O 3 )广泛存在于葡萄、桑棋等植物果实中,它具有抗肿瘤、抗氧化、延缓衰老等功效。下列说法正确的是( )
1 个白藜芦醇分子中含有 6 个 H 2 分子和 1 个 O 3 分子
1 个白藜芦醇分子是由 14 个碳元素、 12 个氢元素和 3 个氧元素组成的
白藜芦醇中 C 、 H 、 O 三种元素的质量比为 14 : 1 : 4
白藜芦醇中氧元素的质量分数为 48 %
The world is changing with every minute, and China___________ with every minute,too.( )
A.is changingB.had changed
C.changed
___________ does your mother go to the supermarket?
Once a week.( )
A.How oftenB.How longC.How far
Annie took a lot of___________ with her mobile phone when she visited the Great Wall last summer holiday.( )
A.photoB.photoesC.photos
Look! The girl___________ red is helping an old man cross the road.( )
A.ofB.onC.in
________do you think of movie Me and My Motherland?
I love it! It's a great movie.( )
A.HowB.WhatC.When