单选题 The ascent of the mountain is ______, but anyone who makes it to the top is rewarded by a spectacular view.
A. helpful B. automatic C. unique D. unpleasant

【正确答案】 D
【答案解析】(unpleasant使人不愉快的)。句意为：山的斜坡让人沮丧，但是到达山顶的人能享受到壮丽的景色。A．helpful有帮助的；B．automatic自动的；C．unique独特的。