問題詳情：
must keep the room clean, so don't throw ________ (垃圾) on the ground.
3. In the 18th and 19th __________ (世紀), many people moved to this city.
4. The trip __________(透過) the forest sounded dangerous.
【回答】
1. rubbish 2. centuries 3. through
知識點：單詞拼寫
題型：單詞拼寫
