【简答题】Dogs are generally called “man's best friend”. They are loyal, funny and loving. They seldom complain and always obey their owners. People who have dogs seem to be happier and healthier than those who...
【简答题】Please give some information about the dvelopment and changes of protected cultivation from 1980s to the present in China . 2、 Why can we assure that "greenhouse will almost certainly survive?" 3、 ...