the earrings must be a present for his mother语法错误?课本上的原话,可是前面加s 后面用a?为什么

用must,might,can’t,could填空The owner be a boy because the earrings be a present for his mother. the earrings must be a present for his mother语法错误?课本上的原话,可是前面加s 后面用a?为什么 You must stop w___ earrings. his,earrings,might,the,present,a,for,mother,be.(连接句子) must be the water I must be the must be the money 高一英语（阅读理解）1.When Christopher Columbus landed on the then unnamed Costa Rica in 1502, he saw many Indians wearing gold earrings. So he thought the land must be rich in gold. He named the place Costa Rica, which means “rich coast 高一阅读理解When Christopher Columbus landed on the then unnamed Costa Rica in 1502, he saw many Indians wearing gold earrings. So he thought the land must be rich in gold. He nemed the place Costa Rica, which means rich coast in Spanish. Must Be The Ganja 歌词 翻译must be the past THE IDEA MUST BE BEST! MUST BE THE MUSIC怎么样 We must be careful_____(cross) the road. The school management must be improved. We must be quiet in the library. the book must be someone___(其他的) We must be l------- to the school