Englishfor English speakers
membrane
Noun
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A membrane is a thin layer of cells or tissue that acts as a boundary or lining that separates two environments.
active
Adjective
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If someone is active, he or she does exercise often or participates often.
She was such an active 80-year-old that she ran the .
Jenkins is an active member of the since he goes to all the meetings.
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A sentence is active if its subject does the action.
"Athena helped Odysseus" is an active sentence because Athena is the one who helped.
complex
Adjective
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If something is complex, it has lots of parts or pieces, or is difficult to understand.
He has constructed a complex computer system to send translated messages between humans and dolphins.
A complex problem that we face today is poverty, especially in Africa.
complex
Noun
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A problem.
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A group of buildings with a common purpose, such as a university or military base.
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A psychologically based dislike or fear of a particular thing.
Jim has a complex about working for a woman boss.
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A thunderstorm that forms when two storm fronts collide.
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A structure with a central atom or molecule that has a weak connection to atoms or molecules around it.