皮皮学，免费搜题
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搜题
【单选题】
那种紫外线可以有效促进爬行动物的维生素D3的合成?A.
UVA
B.
UVB
C.
UVC
D.
UVA、UVB、UVC
拍照语音搜题，微信中搜索"皮皮学"使用
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皮皮学刷刷变学霸
举一反三
【单选题】The BBC has just successfully demonstrated a new digital radio______system.
A.
transaction
B.
transition
C.
transmission
D.
transformation
【多选题】关于茶树鲜叶和茶叶中的芳香类物质,下列说法正确的是( )。
A.
茶树新梢中芳香物质含量,幼嫩叶片大于老叶
B.
茶树新梢中芳香物质含量,春季大于夏季
C.
茶树新梢中芳香物质含量,高山大于平地
D.
青叶醇有顺式和反式两种,顺式有青草气
E.
茶叶中含有棕榈酸、高级萜烯类,这些物质本身无香气,但有很强的吸附性,能吸收香气和异味
F.
一般地说,红茶中的芳香物质种类多于绿茶
【单选题】This digital radio looks fashionable, ______ it often fails to work
A.
and
B.
so
C.
but
D.
or
【简答题】This digital radio looks stylish, _____ it often fails to work.
【单选题】The BBC has just successfully demostrated a new digital radio _______ system.
A.
transaction
B.
transition
C.
transmission
D.
transformation
【单选题】The old radar-and-radio system is becoming______, as new digital technology provides airline pilots with satellite signals to aid in navigation.
A.
absent
B.
missing
C.
without
D.
obsolete
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