He never thought that his success came ________ he least wanted it.
A．until B．since
C．when D．while
Some experts have said that ________ children believe they can succeed, they will never become totally confident of themselves.
A．if B．since
C．once D．unless
Our society insists on regular habits, timekeeping and punctuality, and whether we like it or not, ________ we mean to make our way in society, we have to comply (to act in accordance with a demand, rule, etc.) its demands.
A．whether B．after
C．if D．until
________ the calculation is right, scientists can never be sure that they have included all variables and modeled them accurately.
A．Even if B．As far as
C．If only D．So long as
It is comforting to see that ________， we are doing our part for the environment.
A．as small may be we B．as we may be small
C．small as may be we D．small as we may be
There is no point advocating banning smoking in public ________ the law is introduced.
A．when B．unless
C．since D．because
