Look at the pictures and fill in the gaps with must/mustn't

Riding a bicycle is very useful. But people don't always take a bicycle for the following reasons. One of the reasons is the absence of bicycle lanes. Let's look an adcantages and disadvantages of riding a bicycle and building bike lanes. The most important advantage is more simplier and safer riding for bikers around the city. The disadvantage is that there isn't enough place for bike lanes in the city. So, it will be necessary to allocate part of road or pavement. As a result, there will be no place for pedestrians and road capacity will be reduced. Besides, many pedestrians ignore road signs and go along the bike lanes. This impedes bike traffic and increases the probability of accidents. In addition, a lot of money is required for building of bike lanes since it is necessary to put asphalt, draw markings and place road signs. I believe that in future the bike lanes will be an integral part of roads and a bicycle will become an important part of our life.

In the city houses are taller than in the country - в городе дома выше чем в деревне
in the city bridges are longer than in the country - в городе мосты длиннее чем в деревне
in the city streets are wider than in the country. - в городе улицы более широкие чем в деревне
in the city rivers are dirtier than in the country - в городе речки грязнее чем в деревне
in the country houses are smaller than in the city - в деревне дома меньше чем в городе 
in the country rivers are cleaner than in the city - в деревне речка чище чем в городе
in the country gardens are bigger than in the city - в деревне сады больше чем в городе