Meaning: 'Has' is a form of the verb 'have' used with the past participle to indicate possession or completion in the present context.

Wrong options:

• was: The word 'was' is past tense and does not convey the ongoing relevance of the design, making it unsuitable here.
• had: The word 'had' is past perfect tense, which indicates an action completed before another past action, not fitting the current context.
• is: The word 'is' is present simple and does not convey the completed action of designing the suit, making it grammatically incorrect in this context.

Correct answer: more

Explanation: The word 'more' is used here to indicate a greater degree of ease in moving and lifting, which fits grammatically and contextually as it modifies the adverb 'easily' to enhance its meaning.

Meaning: 'More' means a greater amount or degree, indicating that the suit helps the elderly to perform actions with greater ease.

Wrong options:

• much: The word 'much' is typically used with uncountable nouns and does not fit with 'easily' in this context, as it does not modify the adverb correctly.
• too: The word 'too' implies excessiveness, which does not fit the intended meaning of helping the elderly to move more easily.
• far: The word 'far' is used to indicate distance or extent, which does not apply to the context of ease in movement.

Correct answer: can

Explanation: The word 'can' is a modal verb that indicates ability or possibility, fitting perfectly in the context of what the wearer is able to do with the suit. This aligns with the grammatical structure of the sentence, which requires a modal verb to express capability.

Meaning: 'Can' means to be able to do something, indicating that the wearer has the ability to stand up with the help of the suit.

Wrong options:

• ought to: The phrase 'ought to' suggests a recommendation or obligation, which does not fit the context of ability in this sentence.
• used to: The phrase 'used to' indicates a past habit or state, which is not relevant to the current capabilities provided by the suit.
• must: The word 'must' implies necessity or obligation, which does not convey the ability to perform an action as 'can' does.

Correct answer: so

Explanation: The word 'so' is used here to indicate purpose, connecting the action of injecting air into the suit with the result of the legs straightening. This fits grammatically and contextually as it shows the intended outcome of the action.

Meaning: 'So' means for that reason or in order that, indicating the purpose behind injecting air into the suit.

Wrong options:

• until: The word 'until' indicates a time limit or condition, which does not fit the purpose of the action described in the sentence.
• on: The word 'on' is a preposition that does not convey the intended purpose of the action, making it unsuitable here.
• by: The word 'by' indicates a method or means, which does not express the purpose of the action as effectively as 'so' does.

Correct answer: from

Explanation: The word 'from' indicates the source of the increased strength, fitting grammatically and contextually as it shows that the strength was gained as a result of wearing the suit.

Meaning: 'From' means as a result of or due to, indicating the source of the positive feelings of empowerment.

Wrong options:

• after: The word 'after' indicates a time sequence, which does not fit the context of gaining strength from wearing the suit.
• with: The word 'with' suggests accompaniment or association, which does not accurately convey the source of strength in this context.
• for: The word 'for' indicates purpose or benefit, which does not fit the context of indicating the source of strength.