问题补充：
You’d better go there by train. The train ticket is the airplane ticket.
A. as cheap three times as
B. as three times cheap as
C. three times cheaper than
D. three times as cheaper as
答案：
A. as cheap three times as
B. as three times cheap as
(答案→)C. three times cheaper than
D. three times as cheaper as
解析：考察倍数表达。倍数表达有四种：1. “A+倍数+形容词或副词的比较级+than+B”， 2.“A+倍数+as+形容词或副词的原级+as+B”， 3. “A+倍数+the size/height/length/width， etc+of+B”， 4. “……times+what+从句”。本题考察的是第一种表达。句意：你最好坐火车去那里，火车票价是机票价格的三倍。故C正确。
