So __ _ that all the living things died out gradually .
| A．serious polluted the lake is | B．serious polluted is the lake |
| C．seriously polluted the lake is | D．seriously polluted is the lake |
A fire broke out in the neighborhood last night. By the time the firemen arrived, it .
| A．had been put out | B．would put out |
| C．has been put out | D．was putting out |
For some reason, we hurriedly ended our meeting, a lot of problems to be settled.
| A．leaving | B．to leave | C．leave | D．left |
Either you or one of your students _______to attend the meeting that will be held tomorrow.
| A． are | B．is | C．have | D． be |
— How long has your brother been working in this factory?
— he graduated from college.
| A．When | B．By the time | C．Until | D．Ever since |
---Have you ever had any skin problems _______eating junk food?
---- Yes, two years ago.
| A．close to | B．different from | C．far from | D．connected with |