—What does PM 2.5 mean?
—It's a professional ________ indicating the condition of air pollution.
| A．term | B．item | C．number | D．mark |
Sorry I'm so late, but you cannot imagine __________ great trouble I took to find your house.
| A．what | B．how | C．which | D．why |
She is __________ the newspapers to be thrown away and putting away the rest.
| A．sorting out | B．figuring out |
| C．making out | D．turning out |
__________ young people are making efforts to take more exercise and eat healthily, they are still putting on weight.
| A．Because | B．Now that |
| C．When | D．While |
__________ two giraffes (长颈鹿), Zheng He later brought zebras, shells, elephant ivory back to China after his voyages.
| A．Besides that | B．Except |
| C．In addition | D．Apart from |
Yesterday she sold her car, __________ she bought a month ago.
| A．when | B．where |
| C．that | D．which |