✔ 最佳答案
1. Could 可以用作客套問候語，如Could I have a cup of tea, please? Could you tell me where is the bus stop, please? 書本通常用May I，但Could I 都可以通用，但沒有May you，一定用Could you，怕錯最好用哂Could I, could you，記住要加please (foraml form)，口語可以唔講please.
2. had係have的past tense, 但記住，用had一定要加過去時間，否則就當present tense，如 I don't have a cat at home. I had a cat at home 2 years ago (或者你可以用I used to have a cat at home一樣意思)
3.verb後面99.9%要加to，grammar要求，如use to, need to, get to, have to... 只有少數唔駛用to，如shut, help等等 (只限英文，美文全部會用to)，若然怕錯，全部用+ to啦！
基本上May said that they had to finish their project by the next day, 係錯既，雖然May講(said)呢句話時候係過咗去，但係冇講明係幾時講，所以我諗呢句應該有後尾，如lask week, yesterday, one month ago等等，否則，只能當May啱啱講完，而要用Present perfect tense, May "has just said" that they "have" to finish....... "had"要轉回present tense "have"
4.若果有兩個動作過去已經發生咗，有先後次序，先完成要用past perfect tense, 後完成要用past tense，如I saw a beautiful lady on the other side of the road after I had gone across the traffic light last night. (呢個幾深，會有啲難明，現實生活中99.9%係唔會用到，口語更加唔會講，只係考試用)。唔明最好問英文老師，因為要花多啲時間去理解，若果明白，自然會明Past Perfect Continous tense點用，同一道理。至於Future perfect tense同Future Perfect Continous tense都係同出一徹。
5.been係be既perfect tense, 就係咁簡單，如I have been living in Hong Kong for 10 years.
be通常用係could be, must be, should be, will be等等，perfect tense就係could have been, must have been, should have been, will have been等等… 此外，be係解am, are, perfect tense就自然係has been, have been，用多啲自然會識！
