關鍵詞3：have to

情態動詞have to （口語中說成have got to） 表示客觀需要做的事情，意為“必須；不得不”(也就是客觀條件強迫主語必須得這樣做，沒有商量的余地，預期比較強硬)。 1 have to同情態動詞must 的區別。have to 和must 都有“必須”的意思。但是 have to側重于強調客觀條件需要做的事情。而must 側重于表示說話人的主觀看法，認為有義務，有必要去做某事。例如： I have to clean my room first. You must be here before eight. 2 have to 有人稱和數的變化，其他情態動詞沒有。例如： Mr lee has to work on the farm all day long. You /I can go swimming this Sunday3 have to有多種時態的變化，而can, may等只有過去式等形式。例如： We will have to finish it the day after tomorrow I thought I could sell something used4 have to不能直接用來否定或提問，需要助動詞do / did / does等幫助。而其他的情態動詞一般都可以直接進行否定和提問。

例如： Where do I have to go? May I come in?
You don/'t have to help her with her English =you don’t need to help her with her English 5 have to可以被may 等情態動詞修飾，其他動詞之間不能互相修飾。例如： I think you may have to finish the work today.
重點動詞have 1：實義動詞，本身包含具體的詞意"有"，I have a computer
否定句 :主語+do/does/did+not+have+其他=主語+have/has/had+not+其他
例如：I do not have a computer=I have not a computer
疑問句：Have/has/had+主語+其他=Do/does/did +主語+have+其他？
Have you a computer?=Do you have a computer?

2 Have 助動詞have/has/had+done構成完成時
肯定句：主語+have/has/had+過去分詞+其他 I have finished my work.
否定句：主語+have/has/had+not+過去分詞+其他 I have not finished my work
疑問句：Have/has/had+主語+過去分詞+其他？Have you finished your work?

3 have還可以和很多單詞，特別是那些既是動詞又是名詞的詞連用，構成很多短語，其詞意則是由與其連用的詞語來決定，它的活躍之處也就在于此。例如： have a talk 談話 have a tea 喝茶 have a rest 休息一會兒 have a class 上課 have a hike 遠足 have a picnic 野炊 have a concert 舉辦音樂會 have a visit 參觀；訪問 have a look 瞧一瞧 have a sleep 睡一會兒覺 have的這類短語還有很多，只要大家留意，會在以前學習過的課文中發現很多。這種短語還有自己的賓語或其它成分。例如： What a nice photo! Let me have a look (at it). You'd better have a talk with him. have還可以和表示疾病的名詞連用，表示正在或曾經生過某種疾病。例如： have a headache 頭痛 have a stomachache 胃痛；肚子痛