He reminded me of what I should ______ have forgotten

Being examined twice a year is the rule that every driver _____ obey in this city.

shall we meet your cousin at the station— His plane took off two hours ago, and it reachat 5 pm.

Where are you going for yourholiday–Well, we _______ yet.

People often have this belief _______economic development is bad for the environment, but this does not have to be true.