.No one knows exactly when our ancestors started talking,but new evidence suggests _______might have happened a long time ago.
Every minute should be made full ___ of ___ our lessons well.
It is the first time that Mr. Smith ________ Wenzhou and I’d like to show him around.
They believe that there is __________ in the world.
Jack decided to buy himself an iPhone 4 _______ it means standing in line all night waiting.
________________of the students who took part in the military training(军训) is 450.