The invention of steam engine greatly sped up the industrial revolution, which ________ a lot to the take-off of the world.
| A．turned | B．contributed | C．constructed | D．exposed |
Like ancient sailors, birds can find their way____ the sun and the stars.
| A．used | B．having used | C．using | D．use |
______ he once felt like giving up, he now has the determination to push further and keep on going.
| A．Where | B．As | C．In case | D．Now that |
He wrote many children’ s books, nearly half of____ were published in the 1990s.
| A．whom | B．which | C．them | D．That |
The meeting will be held in September, but____ knows the date for sure.
| A．everybody | B．nobody |
| C．anybody | D．somebody |
_____ the difference between the two research findings will be one of the worst mistakes you make.
| A．Ignore | B．Ignoring |
| C．Ignored | D．Having ignored |