to make a mistake; to be incorrect; to be mistaken
whether or not (in phrases like "I don't know whether or not I can come")
unrelated; irrelevant; unconcerned; unconnected
given that ... it is only natural that ...; ... being the case, it is unavoidable that ...; (precisely) because ...; contrary to expectations ...
to stop (an activity); to cease; to discontinue; to cancel; to abandon; to give up
to think of; to come up with
potentiality; likelihood; possibility; availability
isn't it?; let's ...; why don't we ...; how about we ...