google syntax

1.Use quotes("  ") to search for an exact word. 
"English dictionary" 

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2.Use filetype: to search for specific file format. 
"English dictionary"filetype:pdf 

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3.Search for pages that link to a URL 
    link:http//www.ntcb.edu.tw

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4.Use site: to search within a site or domain.
"English dictionary"site:tw 

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5.Use related: to search for similar URL.
related:http://www.vocabulary.co.il 

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Dictionary Exersice

lift the mood
-make happier
Some research shows the walking or exersicing can make people healthier and lift the mood.

well-being
-a feeling of being happy, healthy, and comfortable
During the winter, having a hot bath provide me a feeling of well-being.

I used Longman dictionary and the reason why I use this dictionary is that it's shows clear on what I search. Also the definitions are clear and easy to understand. There's a special thing I like to use this dictionary is on the bottom of the website, there are some pictures for you to learn. Click on those pictures and it'll shows you the word and the definition of it.