1. 现在进行时表示正在发生的事情或进行的动作，常与now,listen,look等词连用。

结构是主语+be动词(am, is, are)+动词ing.如：It is raining now.外面正在下雨。It is six o’clock now.现在6点了。My parents are reading newspapers in the sitting room.我父母正在客厅看报纸。Look! The children are having a running race now.看！孩子们正在赛跑。问句将be动词移前，否定句在be动词后+not.

2. 一般现在时表示经常反复发生的事情或动作，常与often, usually, sometimes, always, every day(week year…) 等词连用。结构是主语+动词原形；当主语为第三人称单数即he,she, it, Tom, my mother, the boy等词时，动词后加s或es.如：We have an English lesson every day.我们每天都要上英语课。Do the boys run faster than the girls? Yes, they do.男孩比女孩跑的快吗？是的。问句借助于do, does否定句借助于don’t, doesn’t，后面动词一定要还原。

3. 一般过去时表示发生在过去的事情或存在的状态，常与just now; a moment ago; … ago; yesterday; last ( week; month; year; Monday; weekend); this morning等词连用。结构是主语+be动词的过去式（was; were）或主语+动词的过去式。注意：be动词与动词过去式不可同时使用。如：My earphones were on the ground just now.我的耳机刚刚还在呢。Where were you last week? I was at a camp.你上个星期去哪了？我去野营了。What did you do yesterday? I visited a farm.你昨天去干嘛了？我去参观农场了。问句有be动词将be动词移前，没有be动词借助于did，后面动词还原；否定句有be动词在后面加not，没有借助于didn't后面动词还原。