close 较多地用于正式或庄重的文体中，如关闭铁路、公路以及其它交通渠道，要用close。
shut 着重关闭的动作、过程和方式手段。
slam 象声词，指“砰的关上”，或用力关上。
参考例句
1. They shut him from their circle. 他们把他排除在他们的圈子外。
2. When do the pubs shut ? 酒馆什么时候关门?
3. The computers immediately shut off the rocket engines. 于是，计算机立即关闭了火箭发动机。
英英解释
v.
1. move so that an opening or passage is obstructed; make shut
2. become closed
3. prevent from entering; shut out adj.
1. not open
2. used especially of mouth or eyes
