Questions

‘Sitting on the fence’ is the correct idiom used. It is used to describe a person’s lack of decisiveness, neutrality or hesitance to choose between two sides in an argument or a competition, or inability to decide due to lack of courage. Thus, the sentence is grammatically and contextually correct. Thus, the correct formation would be, ‘Decide one way or the other; you can’t be sitting on the fence forever’.

The senior most member of the Chiefs of Staff Committee (COSC) is appointed as its Chairman. Admiral Sunil Lanba is the current and the 23rd Chief of the Naval Staff of the Indian Navy.

'No sooner' is always followed by ‘Than’ and the verb comes before the subject. Thus, the sentence is grammatically and contextually correct. Thus, the correct formation would be, ‘No sooner had he completed his first novel than he fell seriously ill’.