Yuan Longping was a world﹣famous scientist.Because of his achievements,rice_______ has been increased greatly.( )
A.populationB.contribution
C.productionD.introduction
﹣ Who is the_______ runner, Mike or Sam?
﹣Mike is. He is good at running.( )
faster
slower
weaker
Work hard,______ you will get good grades.( )
or
but
and
Many more people have realized saving______ earth begins with small things.( )
a
an
the
Look! Miss Wang is carrying a heavy box. Let's go to help .
My little brother likes to jump up and like a monkey.