1 . Air is ________ , and it is important to the living things on the Earth. (visible)
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2 . Some spiders are good at catching mosquitoes. Most of them can weave webs that are almost ________ . (visible)
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3 . Air is ________ , and it is very essential to human beings. (visible)
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4 . This star cannot be seen by our eyes. (保持原句意思)
This star________ ________ to our eyes.
This star
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5 . “When Rosa and Samuel hid behind the bushes, they were ________ to anyone passing by.”
| A．invisible | B．immense | C．horrified |
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6 . Air is ________ , but there is air around us everywhere. (visible)
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7 . Electricity is _________ as well as sound. (visible)
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8 . Although air is ________ , we can feel it. （visible）
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9 . Oxygen is an ________ gas, but it is very important to many living things. (visible)
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10 . Bacteria are ________ to the naked eyes. (visible)
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