I didn’t quite follow him because he explained the theory _____that is too abstract for me.
Until recently historians assumed that calendars ________ with the advent of agriculture.
. ________ when the boulders suddenly disappeared.
________ from endless homework on weekends, the students now find their own activities, such as taking a ride together to watch the sun rise, more colourful.
When he knew the disappointing result of the exam, he seemed quite _______.
. If the weather had been better, we could have had a picnic. But it ________ all day.