Question

______ he has made up his mind, no one can make him change it.

A．Once

B．Unless

C．Until

D．As

Answer 1

A

试题分析：考查连词辨析。A一旦；B除非，如果…不…；D直到…才；D因为；句意：一旦他下定决心，没有人能让他改变。故A正确。
点评：连词的辨析要放在上下文中进行，特别注意unless=if…not如果…不;该词是考试的重点。