Common Errors in English - Think

think
verb
1
BAD: I was thinking if you would like to have lunch before visiting the museum.
GOOD: I was wondering if you would like to have lunch before visiting the museum.
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To introduce a polite request or invitation, use I was wondering if/whether : 'I was wondering if you'd like to play tennis on Saturday.' 'Sally was wondering whether you could give her some advice.'
2
BAD: We should spend more time thinking why people do such terrible things.
GOOD: We should spend more time thinking about why people do such terrible things.
BAD: While she was away, he often thought on her.
GOOD: While she was away, he often thought about her.
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think about sb/sth (= give a lot of thought to): 'She's worried about her father and can't stop thinking about him.' 'Have you ever thought about what you'd like to do for a living?' 'You look serious - what're you thinking about?'
3
BAD: He's thinking to make another trip to Italy next month.
GOOD: He's thinking about making another trip to Italy next month.
BAD: We're thinking on going to the beach after lunch.
GOOD: We're thinking of going to the beach after lunch.
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When you are talking about possible future actions, use think about/of doing sth : 'They're thinking of starting their own health food business.' 'We're thinking about going to Disneyworld again next year.'
4
BAD: He advised me to think deeply about it before making a decision.
GOOD: He advised me to think seriously about it before making a decision.
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think seriously/carefully (NOT deeply ) (about sth ), especially before making a decision: 'The job has a lot of attractions and in my opinion you should think seriously about it.'
5
BAD: Some foreigners are thinking the Japanese are rich.
GOOD: Some foreigners think the Japanese are rich.
6
BAD: I think she didn't understand what you said.
GOOD: I don't think she understood what you said.
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Do not think (that) is more usual than think (that) ... not . This applies to believe, imagine, suppose, feel etc: 'I don't imagine they'll be coming after all.' 'I don't suppose you could give me a lift?'