is necessary for us to wash hands when we are back home.( )
A.ItB.ThatC.This
Which is____, the blue one or the red one?
The blue one.( )
good
better
best
Please tell me_____you have learnt English.
For three years.( )
how long
how often
how soon
He felt tired, so he stopped______a rest under the tree.( )
having
have
to have
Get up early,_____ you will miss your train.( )
or
and
but
I _____ a math problem with Joe when Mike called me up.( )
have discussed
discussed
was discussing