Правельно ли определены времена?
1. In the seventeenth century, people began to build calculating machines.
2. During the next ten years, Pascal made fifty more machines.
(Past Perfect Continuous)
3. Although an abacus can be very fast, it is not really a machine because it does not do calculations automatically.
4. In the 170s, a German called Leibnitz continued Pascal`s work and made a better machine.
Везде past simple, кроме 3-pres simple.