问题补充:
Was it because of the heavy snowstorm in Europe the flight had to be put off ?
A. which
B. so
C. why
D. that
答案:
A. which
B. so
C. why
(答案→)D. that
解析:考查强调句型。此处because of the heavy snowstorm in Europe是被强调的部分,原语序为:The flight had to be put off because of the heavy snowstorm in Europe.