—Where is our English teacher?
—She is in the classroom, ________ the exercises _________ the students have done at home.
| A．explaining; / | B．explaining; for | C．explained; to | D．explained; from |
Some forms of algae have to growing on ice.
| A．adopt | B．adapt | C．advocate | D．addict |
Antarctica holds 90% of the world’s ice, and most of its fresh water (70%) is in a frozen .
| A．state | B．condition | C．situation | D．solution |
She has a lot of things, so she knows exactly how to deal with such a person.
| A．gone through | B．gone on | C．gone by | D．gone into |
Parts of the cave have been badly affected by rain andto the air.
| A．express | B．excavate | C．exposure | D．expand |
By the time Jack returned home from England, his son from college.
| A．graduated | B．has graduated | C．had been | D．had graduated |