请根据括号中的中文提示、英文释义或句意，写出句中所缺单词，使句子通顺。
We students should do many after-school ____________(活动).
People in different countries speak different l_____________.
It’s _____________(hard or not easy) for me to play basketball well because I can’t run fast.
This boy doesn’t know the ______________(重要性) of study.
L___________, he wasn’t badly hurt yesterday.