... with for & since o For + ( a period of time ) For 10 years For 23 secondso Since + ( a point of time ) Since Monday Since 1989I have studied English for 10 years.She has not seen Lan since ... thành với Since và For. a.Công thứcHas/have +PIIb.Cách chia(+) I(We,you,they )Have worked for three years. He (she,it) has worked for three years.(-)I(We,you,they )have not worked for three ... years. He (she,it) has not worked for three years. Note :have not=havent Has not= hasnt(?) Have I(We,you,they ) worked for three years.? Has he (she,it) worked for three years?Cách dùng:Thì...