Explanation

The phrase "by October next" indicates a future point in time with a completed action.

So, the correct tense is future perfect, i.e., "will have served".

Explanation

Whereas is used to contrast two ideas or qualities in one sentence.

It correctly shows the contrast between "she is funny" and "he is boring."

Explanation

The common idiomatic expression is "You are as cold as ice," meaning emotionally distant or unfeeling.

"Ice" is used to represent coldness in this comparison.

Explanation

Here "Unless" means جب تک

The sentence means "You don't need to go if you don't want to", which is correctly conveyed using "unless."

So, the complete sentence is: "You don’t need to go unless you want to."

Explanation

The word Furniture is a noun.

Economical is an adjective.

Usually, an adjective is used before a noun.

Explanation

The correct sentence would be, "I shall see you tomorrow unless I have to work late."

Unless is used to indicate a condition under which something will not happen.

Explanation

"Who" is used as the subject of a sentence referring to a person.

The sentence is asking about the person performing the action (knocking).

Explanation

The correct phrasing requires "Was the microwave" to form a proper question about the invention of the microwave.

It follows the structure of asking about the invention of a specific item in the past.

Explanation

"That" is correctly used to refer to people or animals in a defining clause.

The sentence means man is the only animal that can think positively about human progress.

Explanation

The correct phrase is "at enmity with", used to show hostility between two parties.

"Enmity" means a state of being actively opposed or hostile to someone.