Onewaytounderstandthousandsofnewwordsistogain__________goodknowledgeofbasicwordformation.
Mycoat__________therebehindthedoor.Can’tyouseeit?
Ifasubstanceisdissolvedinwaterorheated，itmay（）agas.
Modern____perhapscausesmoreproblemsthanitsolves.
Thesmallmountainvillagewas（）bythesnowformorethanonemonth.
Duetothebadweathertheplanewas____fortwohours.
