단원은 현재 진행형이지만 관련 없는 문제도 있는거가테요..
1. What they ( )so far is using sea water as a source of electricity
A.do B.had been doing C.have been doing D.did

2.They ( ) thier classroom. It looks completely new again
A.have redecorated B.were redecorated C.were redecorating D.will redecorate

3.She used to complain about everything but now she ( ) a lot
A.changed B.had changed C.has changed D.had been changing

4.쟤는 만날 수업 시간에 잠만 자.(is,sleep )
→He [ ] in class
()안에있는거 활용해서 []에 뚯에 알맞게 넣어주세요