Early this year, thousands of migrant _______ workers cancelled their insurance due to the lack of _______ policy to transfer insurance between difference regions.
| A．the; the | B．the; a | C．/; the | D．/; a |
Helen devoted herself _______ to her research and became a top scientist in the field of applied physics.
| A．seriously | B．extremely | C．entirely | D．strictly |
Vitamin D helps our bodies make a special chemical，and this special chemical，
__________，affects our brains，making us feel happy.
| A．in turn | B．in particular | C．in advance | D．in short |
. Everyone must have known the death of the waitress，________?
| A．must they | B．mustn't they | C．haven't they | D．have they |
----Tony is such a selfish person.
----I agree. Never again _________ with him.
| A．1 will deal | B．I do deal | C．will I deal | D．do I deal |
After driving for 20 miles，Jackson realized that he _______ in the wrong direction.
| A．was driving | B．drove | C．had been driving | D．had driven |