The professor warned the students that on no account _____________ use mobile phones in his class.
should they
they should
dare they
they dare
Had the government limited the sales of cars much earlier, traffic jam and pollution _______so serious now.
____today, he would get there by Friday.
Had they known what was coming next, they _________second thoughts.
Had you taken it more seriously, you ________ such a silly mistake.
_________, the world would be more harmonious.