—Sorry indeed, I ________ to your birthday party if …
—Forget it. I know you were out on business.
| A．must come | B．would come | C．must have come | D．would have come |
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．
| A．make | B．would make | C．will make | D．will have made |
—Yeah, but not now, Tom． —Okay, I．
| A．just ask | B．have just asked | C．am just asking | D．was just asking |
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．
| A．could seem | B．might seem |
| C．should have seemed | D．must have seemed |
The average cost of school residential trips was ￡ 48 in primary schools and ￡ 55 in secondaries in 2003, but ￡ 144 and ￡ 274 in 2009．
| A．regularly | B．relatively | C．respectively | D．responsibly |
For areas that receive regular and plentiful rainfall, such detailed crop monitoring（监测）might not be useful or ;
| A．economy | B．economic | C．economical | D．economics |