Correct Answer: B

Rationale: A device is defined as a tool or piece of equipment designed to serve a specific purpose. It is used to perform a particular function or task. An idea or concept (Choice A) may lead to the creation of a device, but they are not devices themselves. Choice C, referring to a small part of a larger structure, does not encompass the general definition of a device which implies standalone functionality. Choice D, an accessory for fashion, is entirely unrelated to the usual understanding of a device, which focuses on functionality rather than aesthetics.

Correct Answer: B

Rationale: The correct answer is B: 'To lift up or place in a higher position.' Elevate means to raise something to a higher level or position. Choice A, 'To lower,' is incorrect as it is the opposite of elevate. Choice C, 'To flatten,' is incorrect as it means to make something level or smooth, not to raise it. Choice D, 'To remove,' is also incorrect as it means to take something away, not to lift or raise it.

Correct Answer: B

Rationale: A device is defined as a tool or piece of equipment designed to serve a specific purpose. It is used to perform a particular function or task. An idea or concept (Choice A) may lead to the creation of a device, but they are not devices themselves. Choice C, referring to a small part of a larger structure, does not encompass the general definition of a device which implies standalone functionality. Choice D, an accessory for fashion, is entirely unrelated to the usual understanding of a device, which focuses on functionality rather than aesthetics.

Correct Answer: B

Rationale: Labile means something that changes rapidly and often. In this context, 'Stable' (Choice A) is the opposite of labile, 'Unchanging' (Choice C) and 'Rarely changing' (Choice D) do not capture the essence of labile. Labile is specifically used to describe something that is easily altered, constantly changing, or unstable, hence the most suitable choice is 'Changing rapidly and often' (Choice B).

Correct Answer: B

Rationale: In the given sentence, the past continuous tense 'was studying' is the most appropriate choice to indicate an ongoing action in the past. 'Was preparing' (choice A) implies a completed action rather than an ongoing one. 'Had studied' (choice C) is past perfect tense, which is not suitable for indicating an ongoing action. 'Is studying' (choice D) is present continuous tense and does not fit the past context of the sentence.