... necessity2)lack of necessity (negative)I have to go to class todayI don t have to go’ to class today.I had to go to class yesterday.I didn t have to go to class yesterday.Will1) 100% certainty2) ... to 1)advisability2)90% certaintyYou ought to study tonight.She ought to do well on the test. (future only, not present)You ought have to studied last night.She ought to have done well on the test.Had ... easily.(may/ ought to/ will/ might)35. I’m not sure where to go for my holiday, but I …… go to China. (should/ may/ have to/ needn’t)36. we had free tickets, so we ……….pay to get into the concert....