Meaning: 'Microelectrodes' are small electrodes used to detect electrical activity in the brain.

Wrong options:

• able to control the hand: This phrase describes an action and does not fit as a noun in this context.
• going through: This phrase suggests a process or action, which does not fit as a noun here.
• which had been: This phrase is a relative clause and does not serve as a noun, making it grammatically incorrect.
• precisely: This adverb indicates exactness but does not fit as a noun in this context.
• which was: This phrase is a relative clause and does not function as a noun, making it inappropriate here.
• fortunately: This adverb expresses a positive outcome but does not fit as a noun in this context.

Correct answer: which was

Explanation: The phrase 'which was' serves as a relative clause that provides additional information about the computer. It fits grammatically as it connects the noun 'computer' to the description of its function.

Meaning: 'Which was' introduces a clause that describes the computer as running a complex program.

Wrong options:

• able to control the hand: This phrase describes an ability and does not fit grammatically as a relative clause.
• going through: This phrase suggests an action and does not function as a relative clause.
• microelectrodes: This noun does not fit as it does not relate to the description of the computer.
• precisely: This adverb does not fit as it does not serve as a relative clause.
• which had been: This phrase is a relative clause but does not fit the context of describing the computer's current state.
• fortunately: This adverb does not fit as it does not serve as a relative clause.

Correct answer: able to control the hand

Explanation: The phrase 'able to control the hand' describes the woman's newfound ability and fits grammatically as a predicate complement. It is contextually relevant as it highlights her progress after training.

Meaning: This phrase indicates that the woman gained the ability to manipulate the robotic hand.

Wrong options:

• going through: This phrase suggests a process and does not describe an ability, making it grammatically incorrect.
• microelectrodes: This noun does not relate to the woman's ability and does not fit contextually.
• which had been: This phrase is a relative clause and does not describe an ability, making it inappropriate here.
• precisely: This adverb does not fit as it does not describe an ability.
• which was: This phrase is a relative clause and does not convey the woman's ability.
• fortunately: This adverb does not describe an ability and is not relevant in this context.

Correct answer: which had been

Explanation: The phrase 'which had been' serves as a relative clause that provides additional information about the level of control and flexibility. It fits grammatically as it connects to the previous statement about her control.

Meaning: 'Which had been' introduces a clause that describes the previously unseen level of control.

Wrong options:

• able to control the hand: This phrase describes an ability and does not fit as a relative clause.
• going through: This phrase suggests an action and does not function as a relative clause.
• microelectrodes: This noun does not relate to the description of control and does not fit contextually.
• precisely: This adverb does not fit as it does not serve as a relative clause.
• which was: This phrase is a relative clause but does not convey the idea of something previously unseen.
• fortunately: This adverb does not fit as it does not serve as a relative clause.