学进去

仔细阅读下面五个句子，然后用下面方框中所给的单词或短语填空，使每个句子在结构、句义和逻辑上正确。(提示：方框中有两个单词或短语是多余的。)

spread/drop/mean/put out/stared/ courage/set out

 
1．It will bring danger to all ocean life if sharks' numbers ________ too low.
2．We shouldn't forget where we came from as we ________ on our new journey.
3．Tom went to basketball practice with ________ rather than fear in his heart the next day.
4．They ________ in disbelief at the black smoke rising above the burning building.
5．John is ________ and only thinks about himself and doesn’t treat others nicely.