They are broadening the bridge to speed up the flow of traffic.【高考试题】They are broadening the bridge to ______ the flow of traffic. (2011山东卷)A. put off B. speed up C. turn on D. work out【答案解析】答案为B。speed up在此表示“（使）加快速度”。句意为：为了加快交通流量的速度，他们正在给大桥加宽。其余三项：A项表示“推迟”，C项表示“打开（开关）”，D项表示“算出”，均与句意不符。四个选项的意思及用法如下：◆put off(1) 推迟，延期。如：We decided to put off our holiday to [till, until]next month. 我们决定把假期推迟到下个月。Never put off till tomorrow what may be done today. 今日事，今日毕。注：后接动词时，要用动名词。如：We decided to put off leaving. 我们决定推迟动身。(2) 推脱，搪塞。如：I put him off with a promise to pay him next week. 我搪塞他一下，答应下周还他钱。I won’t be put off with such weak excuses. 我是不会被这样一些站不住脚的借口敷衍过去的。(3) 使不高兴。如：What he said put her off. 他说的话使她不高兴。His bad manners put all of us off. 他的恶劣态度使我们大家都很反感。◆speed up(使)加速。如：The train soon speeded up. 火车不久就加快了速度。Soon he speeded up the car. 不久他就加快了车速。◆turn on(1) 打开Please turn the lights on for me; it’s getting dark. 天黑了，请帮我打开灯。(2) 攻击；反对The dog turned on me and bit me in the leg. 这狗向我扑来，咬了我的腿。◆work out(1) (计)算出He worked out the maths problem in five minutes. 他五分钟就算出了这道数学题。He told me to work out the exact figures. 他叫我算出确切的数字。(2) 制订出，研究出，想出，作出I’ll try and work something out. 我要设法想个办法出来。We must work out a plan as soon as possible. 我们必须要尽快制定出一个计划。(3) (有)结果，产生结果(www.nmet168.com)Things worked out quite well. 事情的结果很不错。 说明:引用此文请注明出处,并请保留该文章链接地址,谢谢~~