问题补充：
It is said that the temperature is unusual mainly global warming caused by human activities.
A. in spite of
B. by means of
C. in case of
D. on account of
答案：
A. in spite of
B. by means of
C. in case of
(答案→)D. on account of
解析：考查介词短语辨析。A不管；尽管；B通过，借助于；C以防；D由于；句意：据说温度升高主要是由于人类活动导致的全球变暖引起的。根据句意说明D正确。
