1 . Water had also appeared on other planets like Mars but, ________ (不像) the earth, it had disappeared later. (根据汉语提示单词拼写)

2 . Some people volunteer to help people __________ (在困难中). (根据汉语提示完成句子)

3 . Why did you_____（投票）against Mr Smith at the meeting? （根据汉语提示单词拼写）