Select the most appropriate word to fill in the blank.

I ______ something burning now.

smell

I smell something burning now.

Explanation:

• Smelt: This is the past tense of "smell," but the sentence is in the present tense, so it's not the correct choice.

• Have been smelling: This phrase is in the present perfect continuous tense, but it's not the most suitable choice in this context. The sentence doesn't require a continuous action; rather, it's describing a simple observation.

• Smell: This is the correct choice. The verb "smell" is used in the present tense to indicate that the speaker is currently perceiving a scent.

• Have smelt: This is the past participle of "smell," used in the present perfect tense. However, the sentence is in the present tense, so it's not the best fit here.