Question

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

A．Unless

B．Once

C．Until

D．As

Answer 1

B

试题分析：考查连词辨析。A除非；B一旦；C直到…才；D当…时；句意：一旦他下定了决心，就没有人能让他改变。故B正确。
点评：连词的辨析也要放在上下文中进行，要注意unless用法，要把它改成if…not…便于理解。