A:含有共价键的化合物一定是共价化合物
B:晶体中一定存在化学键
C:含有离子键的化合物一定是离子化合物
D:金属键越强,金属越活泼,金属熔点越高
4×3x+7x=____
This is a farm.It is____and warm today.I can see a____and her three children,three____,two____,a____and a____on the farm.There is a____on the left.Behind the farm there are three high____.In the sky there are____and ____.
下列物质中,属于饱和一元脂肪酸的是( )