Quotation Marks or Inverted Commas are used to enclose spoken words in a sentence. They may be double “ ” or single ‘ ’

He was going out to dinner that day but asked to be excused on account of ‘the death of a dear old friend’. ‘Well, Hardy,’ said Nelson, ‘how goes the day with us?’ ‘Very well,’ replied Hardy.
‘I hope,’ said Nelson, ‘none of our ships have struck?’ Hardy answered that there was no fear of that.

# If one set of spoken words is enclosed in another the first and last quotation marks should be double, and the inner ones single.

‘What did mother say to you?’
“What did mother say to you?”

“She said: ‘Be careful not to catch cold.’ ”