1. When did master lose Chuchu?
2. Master lost Chuchu when they went out for a walk.
3. You must be master of your circumstances.
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#2 is the answer to the question 1. Will you look at the word 'master'? There is no article before 'master.' Can we use that way? In an example sentence as in #3, we can find 'master' without an article. According to the explanation of the dictionary, 'the article' is often omitted in that case. Can we find such an explanation in any English dictionary? Or is that a wrong explanation?
1 answer
In this case there should be a modified before "master". "When did his master lose Chuchu?" "His master lost Chuchu..." In the third sentence, "master" needs no further modifier.