7.
Your Answer is
Correct Answer is B
Explanation
contraption "exquisite design", here refers to the prototype of the bar code scanner.
A/B/C items all refer to unknown,
A item: mixture.
Item B: Substance.
Item D: It is an informal expression.
7.
Your Answer is
Correct Answer is B
Explanation
contraption "exquisite design", here refers to the prototype of the bar code scanner.
A/B/C items all refer to unknown,
A item: mixture.
Item B: Substance.
Item D: It is an informal expression.