Experts say walking is one of the best ways for a person to _____ healthy.
#81811
A
preserve
B
stay
C
maintain
D
reserve
推荐题目
Astronauts in a spaceship have to _______weightless conditions _______are quite different from ______are on the earth. 
#78411
A
do with; which; those
B
deal with; that; that
C
solve; that; what
D
face; which; these
Rather than ____ on a crowded bus, he always prefers _____ a bicycle.
#68619
A
ride; ride   
B
riding; ride   
C
ride; to ride   
D
to ride; riding