China needs to strike a balance between maintaining a ______ fast and stable development and economic structural adjustment. 

Pop music is ____ an important part of society____ it has even influenced our language.

The teacher criticize me, so I must finish my essay about agriculture,farmer and rural areas today______.

Mr. Brook didn’t come back at the usual time last night. ______, he met some friends and stayed out until midnight.

Though many extra trains and buses are used to carry passengers, traffic tools are still ________ needed during the Spring Festival.