Test incompl/inter-347, User's Answer 6

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English Language Tests, Intermediate level

ESL/EFL Test #347 "English Slang Idioms (68)", question 6

"If we get that grant that you applied for, that will be a major ......... in your cap. The boss is going to be very thankful," Linda said to Derek.

(a) patch
(b) update
(c) button
(d) feather

English Language Tests, Intermediate level

ESL/EFL Test #347 "English Slang Idioms (68)", answer 6

"If we get that grant that you applied for, that will be a major feather in your cap. The boss is going to be very thankful," Linda said to Derek.

Correct answer: (d) feather

Your answer was: incorrect
"If we get that grant that you applied for, that will be a major patch in your cap. The boss is going to be very thankful," Linda said to Derek.
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Does to be major feather in one's cap mean that it is the highlight of one's doing something or anything at large?