强调类信号词：in fact，as a matter of fact , actually, especially particularly, in particular, more importantly
时间类信号词：at that time, at the same time,meanwhile, since that time, during that time/period, in1980s, medieval中世纪的，before the industrial revolution
给建议：I want you to; I recommend you to; never;I'd like to see
表示命令，要求，必须，应该：order,command,require,request,ask
表目的:purpose/aim/target/goal/in order to
表惊奇：surprised,shocked,amazed,struck,not expected
