The correct answer is Always thinking of only one thing. Let's look at the meaning of the given idiom: One-track mind: used in reference to a person whose thoughts are preoccupied with one subject or interest.

The correct answer is 'at a fast pace'. In the given sentence 'On the double' is an idiom. The meaning of it is as follows: On the double: very quickly and without any delay.

The correct answer is "beyond one's capability to understand something". Key Points. Given Idiom: Over one's head means too complicated to be understood by one. For example, My jokes always seem to go over one's head.

The given idiom is 'a fair-weather friend'. This idiom means - a person whose friendship cannot be relied on in times of difficulty. For example: Don't rely on her, she is a fair-weather friend.

The correct answer is "to be the person in charge". Key Points. Given Idiom: To call the shots means to be the person in charge, to have control over the progress of a situation. For example, With no boss to call the shots, he drew ideas from all over.

someone who is uncomfortable in a specific situation: I felt like a fish out of water at my new school.

The correct answer is at a rapid pace. Given Idiom: By leaps and bounds means rapidly or in fast progress.

The Harappan civilization was characterized by its well-planned cities and advanced infrastructure. Some of the major cities of the Harappan civilization include:

1.            Harappa: Harappa was one of the first cities to be excavated in the 1920s and gave its name to the entire civilization. It is located in present-day Pakistan and was a significant center of the ancient Indus Valley civilization.

2.            Mohenjo-Daro: Mohenjo-Daro, meaning "Mound of the Dead," is another major city of the Harappan civilization, located in present-day Pakistan. It was one of the largest and most advanced cities of its time, featuring complex urban planning and sophisticated drainage systems.

3.            Kalibangan: Kalibangan is located in present-day Rajasthan, India. It is notable for its unique fire altars and is an important archaeological site belonging to the Harappan civilization.

4.            Lothal: Lothal is situated in present-day Gujarat, India. It was a vital trading center, known for its advanced dockyards and extensive trade connections with other civilizations.

5.            Dholavira: Dholavira, located in the Rann of Kutch in present-day Gujarat, India, is known for its intricate urban planning and large water conservation systems. It is one of the five largest Harappan sites in the Indian subcontinent.

6.            Rakhigarhi: Rakhigarhi is one of the largest sites of the Harappan civilization, located in present-day Haryana, India. It is still being extensively studied by archaeologists and has provided valuable insights into the life and culture of the ancient Indus Valley people.

These cities, along with numerous smaller settlements, formed the backbone of the Harappan civilization, showcasing their advanced urban planning, architecture, and social organization.