A travel blogger is writing about her habits. Help her complete this diary entry by choosing the correct option.

I prefer ___ by train to ___ by plane.

The correct answer is travelling ... flying.

When using "prefer" to talk about general preferences, we use the pattern "prefer + verb-ing + to + verb-ing." The preposition "to" connects the two gerunds: "prefer travelling to flying." Note that both gerunds must match in form — you cannot mix a gerund with an infinitive or a bare verb in this pattern.