Was it because of the heavy snowstorm in Europe the flight had to be put off？A. whichB. s

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

D. that

解析：考察强调句型。It is/was被强调成分that/who其他成分；这是强调句型的基本结构。本题强调的是介词短语because of the heavy snowstorm in Europe。故D正确。