2. I usually ... to work, but today I ... because my car is broken. a) Drive, am walking b) Am driving, walk c) Drive, walk d) Am driving, am walking

The correct answer is 'c) Drive, walk'. The first part of the sentence talks about the usual action that is 'drive'. The second part talks about what happens now due to broken car, so we use 'walk' as a present tense.
Answer: c) Drive, walk