皮皮学，免费搜题
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【判断题】
环节动物的生殖系统来源于内胚层。A.
正确
B.
错误
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】—Are there any boats in the river? —No, _____. [ ]
A.
there isn't
B.
there are
C.
there is
D.
there aren't
【单选题】— Are there any pictures on the wall? — No, ______. [ ]
A.
there is
B.
there are
C.
there isn't
D.
there aren't
【单选题】— people in the room? —Yes, there are. [ ]
A.
Is there a
B.
Are there any
C.
Is there any
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