在下列各句的空白处填入一个适当的词, 使句子意思完整，语法正确。
The best way to improve your English is to an English club.
Most teenagers are of snakes. They are dangerous animals.
The boy is old enough, he should be to choose his own friends.
I don't want to let my mother , so I'll study hard to get good grades.
Bob is easy to get with. His classmates like to be friends with him.
