She watched the boat sail out to sea until it ___ (appear) over the horizon.
问题描述：
She watched the boat sail out to sea until it ___ (appear) over the horizon.
括号中的词变为适当的形式填入空白处,略作说明,顺便翻译一下句子.谢谢!
答
She watched the boat sail out to sea until it (disappeared) over the horizon.
在appear的前面加上【否定前缀dis】,就成了appear “出现”的反义词disappear“消失”.在 disappear的后面加上【过去时后缀ed】,就构成了disappear的过去式disappeared.