Explanation

• D.O letter means Demi-official letter.
• ...
• D.O letter is written by the senior officers of state and central government to others in DO letter format.
• DO letter means an official letter after many reminders to get a work expedited
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• DO stands for Demi Official. It is used in correspondence between government officers to draw the personal attention of the addressee officer.
  
  

Explanation

The idiom once in a blue moon means on rare occasions or rarely.

The idiom means something that happens very rarely or seldom.

It emphasizes infrequent or unusual events.

Explanation

Most abundant element in Earth crust is Oxygen.

Oxygen in the crust is (46.1%).

The chemical formula of oxygen (dioxygen) is O2.

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List of 10 Most Abundant Elements in the Earth's Crust

Explanation

Jabal al-Nour, also known as the "Mountain of Light"

It is located in the Hejaz region of Saudi Arabia, near Mecca. 

Jabal al-Nour is home to the Cave of Hira

Where the Prophet Muhammad received his first revelation

It is also known as Jabal al-Quran and Jabal al-Islam

Explanation

Terrible means خوفناک

Soothing means سکون بخش

Explanation

It was raining yesterday, so we did not go out.

We use Past Indefinite Tense/Past Simple Tense with Yesterday.

Formula of Negative sentence of Past Indefinite Tense:

Subject + did + not + first form of a verb + object.

Explanation

"We use 'will purchase' to express your intent to buy something in the future if you have the money."

 The modal verb 'will' is used to express future tense,

while 'purchase' is the base form of the verb used to describe the action of buying something.

Explanation

The Al-Masjid an-Nabawi is the second mosque built by the Islamic prophet Muhammad in Medina

مسجد نبوی is a mosque in the city of Madina in the Saudi region of the Hejaz

مسجد نبوی the second largest mosque and the holiest site in Islam

The construction of مسجد نبوی started in: 1 Hijir

مسجد نبوی was built by the Holy Prophet (PBUH) himself, next to the house in 622 AD (first Hijri).

On 29th Hijrah was مسجد نبوی expanded

Height: 104 m

Burials: Abu Bakr, Umar

Minaret(s): 10

Explanation

Hazrat Zaid bin Haris (RA) was the first Muslim among slaves.

The name of Hazrat Zaid bin Haris (RA) is mentioned in Surah Al-Ahzab (33rd Surah of Quran)

Zayd ibn Ḥāritha al-Kalbī was an early Muslim, Sahabi, and the adopted son of the Islamic prophet, Muhammad. 

Born: c. 581 CE Najd, Arabia (present-day KSA)

Died: c. 629 (aged 47–48) Mu'tah, Byzantine Empire (present-day Jordan)

Cause of death: Killed at the Battle of Mu'tah

Resting place: Al-Mazar, Mu'tah

Explanation

Horticulture is the agriculture of plants

Agrostology: Study of Grasses 

Agronomy: soil management and crop production 

Odontology: Study of teeth 

Arthrology: Study of joints 

Nephrology: Study of kidneys

Hematology: Study of blood  

Dermatology: Study of skin