He___ have attended the meeting this morning. He has been staying at my home for a whole day.
President Bush was in Omaha this morning to deliver a speech, but he the city by the time the shooting took place.
If the researchers are successful, they an important step in reproducing the way that humans use cognition(认识力)to interact(交流;互动)in their world.
—Yeah, but not now, Tom. —Okay, I .
The next generation of telescopes will reveal(显露;揭示)new parts of our universe that will seem surprising, just as the moon’s craters(坑) when observed 400 years ago.
The average cost of school residential trips was £ 48 in primary schools and £ 55 in secondaries in 2003, but £ 144 and £ 274 in 2009.