________ after the World War II, the United Nations has been actively carrying out its convention to stop wars and bring peace to nations worldwide.
A.Established
B.Being found
C.To be established
D.Having been established

The foundation of all other branches of mathematics is arithmetic,_____science of calculating with numbers.
A.is the
B.the
C.which the
D.because the

In the northern and central parts ofIdahoand Churning rivers ___________ .
A.majestic mountains are found
B.found majestic mountains
C.are found majestic mountains
D.finding majestic mountains

British and Australian people share the same language, but in other respects they are as different as __________
A.cats and dogs
B.chalk and cheese
C.salt and pepper
D.turn a deaf ear

It was wrong of you not to call the fire brigade at once.
A.You didn't call the fire brigade because it was wrong.
B.Calling the fire brigade must be done at once.
C.You should have called the fire brigade at once.
D.The fire brigade was called at the wrong time.

A.architect
B.electric
C.mineral
D.luxury

A.assassinate
B.contributor
C.agriculture
D.arithmetic

All members of my family are aware of the need to obey the family rules.
A.well
B.much
C.greatly
D.far

John __________ this task yesterday morning, but I did it for him. He owes me a thank-you.
A.must have completed
B.should have completed
C.could have completed
D.may have completed

I walked away as calmly as I could__________ , they would have thought I was a thief.
A.In case
B.If so
C.Or else
D.Owing to