(2013·高考湖南卷)If nothing________，the oceans will turn into fish deserts

The president has decided to put _____ he thinks is energetic, experienced and has good qualities in the position of the leadership of the firm.

We can make plans to visit the _________ children in the hospital.

Our friendship ourchildhood has lasted for years

I have experienced quite a number of cases ______ I really wanted to help but could not find anything to _______ [ ]