It is important for us       English well.

A．studying

B．study

C．to study

D．studied

-- The math problem _________ is not difficult.
--- But after several tries , I have to give up _________ on it .

A．it’s , working

B．itself , to work

C．itself , working

D．its , to work

Don’t jump to a conclusion! Let’s _______ the problem first.

A．discussion

B．discussing

C．discuss

D．to discuss