NA为阿伏加德罗常数,下列叙述正确的是( )
I think it's useful for you ______ a second language.( )
learn
to learn
learning
to learning
My bike was broken. It ______ me two hours to walk home.( )
cost
spent
took
paid
He lost ______ new pen yesterday.( )
him
his
hers
her
There ______ a post office and two restaurants across from the street.( )
is
are
has
have
Tina is ______ English girl, but she lives in China.( )
a
an
the
/