Question

Choose the option that best fills in the blank:

I have sung the same song _____.

• A. seldom
• B. always
• C. twice
• D. ago

Answer 1

The correct option is C twice

Here, 'twice' as an adverb of frequency is correct because it implies two times or on two occasions. Here, the same song has been sung on two occasions.
'Seldom' as an adverb implies not often.
'Always' as an adverb implies at all times or on every occasion.
'Ago' as an adverb is used in expressions of time with the simple past tense to show how far in the past something happened.