Ithinkthe______(four)lessonisthemostdifficultinthisbook.
Wecanseesomebirdsoverthere.(对画线部分提问)
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Theseare______.Youcanbuyapairforyourmother.
()What's that ____ English?
About ________ percent of the earth's surface is covered with water
Oneday,MrGreenaskedMrsGreen______(go)shoppingforhim.