用方框中所给单词的适当形式填空，每词限用一次。

worry,  they,  shark,  sleepy,  towards

Take some rest after lunch and you won’t feel ________in the afternoon. .
When the child saw her parents waiting at the school gate, she ran ________ them.
Don’t _______ about your exams, everything will be fine.
To protect________, scientists suggest the people stop fishing in some parts of the ocean.
My host family is really nice .They try _____ best to make me feel at home .