1- (could be at..)/(have to take..)
2- (cant..) (mustn’t could work if ur in the Uk I think)
3- (had to sit..)
4- (what)
5- they all work, but since its not a question, u can use (should, or must,) but since Im guessing ur not in the uk, its best if u use (should)
6- I think its (has to be..)
I hope I helped! :))
Answer: the answer is c which is sink .
Explanation: hope it helps you buddy .Please give brainliest .Thanks .
So the answer would be fd and df
