Work hard while you are young,( ) you won;t be useful to people in the future.

问题描述:

Work hard while you are young,( ) you won;t be useful to people in the future.
A.and B..or C.but D.so

B.or
or在这里=otherwise,译为否则.这里意思发生转折
由于前后时态不一致,所以不选but