Fill in the correct passive form of the verbs in bracket. 1) the eiffel tower (visit) by about six milliom people each year. 2) the exhibits in the museum must not ) 3) luckily, the fire out) before anyone got hurt. 4) jason believes that all types of public transport ) by natural gas in the future.
1. is visited
2. be touched
3. had been put out
4. will be powered