Find the mistake which needs correction

If we will reduce the speed of population growth, there will be less pressure on the earth.
A.will reduce
B.population growth
C.less   
D.on

Knowing several ___ helpful if you work for an international corporation.
A.languages are            
B.language is                  
C.languages is
D.language are

The charity received £50,000 from an anonymous________ .
A.volunteer 
B.provider
C.donor
D.offer

We would save thousands of lives if we ______out the remedy for the flu.
A.had not found      
B.found
C.find
D.will find

I don't really want to go to their party, but I probably will go. They'd be offended if I_____ go.
A.didn't
B.don't
C.will
D.will not

If you hadn’t watched that late comedy last night, you___sleepy now.
A.wouldn’t have been
B.wouldn’t be
C.might have not been      
D.wouldn’t have been being

Let’s start by agreeing to one thing: the police should keep away from the place as long as the fans ___ trouble.
A.won’t make
B.won’t be making
C.wouldn’t make    
D.don’t make

If it_____ convenient, let's go out for a drink tonight.
A.be     
B.is
C.was
D.were

You ___ no trouble at school if you had done your homework.
A.had
B.would have
C.will have
D.would have had

The zookeeper would have punished her with a fine if she ___ the animals.
A.feeds
B.fed    
C.had fed
D.will feed