B. Rewrite each of the following sentences, using the construction with the pronoun,
followed by the verb, followed by an infinitive:
1. Walking in the morning is good for health.
2. Crossing the large river would be very difficult.
3. Achieving all is not possible.
4. Skiing down the mountain was exciting.
​5. Doing exercises necessary for body building.
6. Visiting America was a wonderful experience.