1 . You can spend three days________ the rainforest with a local guide and enjoying the plants and animals unique to the rainforest.

A．happening

B．including

C．exploring

D．practising

2 . New medicine and instruments are being developed every day to ____________ life.

A．extend

B．expose

C．explore

D．exchange

3 . The old rules have to be ____________ because they only applied to the circumstances that existed when they were made a hundred years ago.

A．organized

B．impressed

C．explored

D．revised

4 . It is said that the early European playing-cards were __________ for entertainment and education.

A．explored

B．applied

C．designed

D．exchanged

5 . The visiting president answered journalists’ questions, saying the two countries should seek common ground and __________differences on many problems.

A．examine	B．explore
C．assume	D．reserve

6 . If a ball is placed near a fire, the ball will _______.

A．explore

B．extend

C．exchange

D．expand