Limited natural resources should be made full use of ________ the ________ need of energy.

Last Friday, we had a great time_______ chess in the park.

It is known to us all that the 11th national games emblem _______ many different meanings．

下列各句中，没有语病的一项是（ ）

We may find that learning a foreign language does not have to be ____learning our mother tonguebut can in fact be as easy [ ]