单选题 By the first decade of the 21st century, international commercial air traffic is expected ______. vastly beyond today's levels.
A. to have extended B. being extended
C. to be extending D. having been extended

【正确答案】 A

【答案解析】[解析] expect后面跟带不定式的复合结构：expect sb．to do sth．。如果要表示“预料在将来某个时间某人会做完某事”，就应说expect sb．to have done sth．(后面跟一个表示时间的状语)，因此变为被动语态就成了本题的commercial traffic is expected to have extended beyond today’s levels。