Прочитайте текст. Выберите один из предложенных вариантов ответа. The invention of the wheel didn't only improve transport, but also (A1)... sports which can take many forms. The two wheels on a bike take you much faster and further than your two feet. The inventor of rollerblading decided to put a line of wheels on his shoes. Some people say the skateboard (A2) by surfers who wanted the same experience on land as on the sea, so they put wheels on small boards. Although wheels can help us move more easily, these forms of mountain biking up and down tracks in the countryside still (A3) ... a lot of energy. It certainly keeps you fit, and skateboarding (A4) ... you out of breath as much as jogging. I tried rollerblading for the first time the other day, and after an hour, I was exhausted! Al. 1) was produced A2. 1) had invented A3. 1) require A4. 1) left 2) had produced 2) was invented 2) was required 2) is left 3) is producing 3) was inventing 3) has been requiring 3) has left 4) will produce 4) will be invented 4) will be required 4) will leave 5) produced 5) invents 5) required 5) was leaving