Is there anyone who is an expert at playing Civilization V?

I can't get past level four in the full English version.

In the fourth level, you need to make reasonable use of diplomacy. For technology, research crossbows and cavalry. Use two swordsmen and two archers to destroy a city first, then use money to buy peace. Once health is fully restored, destroy another city, and repeat this process (it's best to build roads to connect your cities). After the first country is destroyed, if the second country declares war, try to deploy crossbows. Once you have enough money, make peace and use a large number of crossbows to surround their cities, with one cavalry outside. Attack suddenly at the right moment. It is estimated that at most five crossbows can take down a city, then use cavalry to occupy it, and then make peace again. Although this method is slow, it is much simpler compared to a conservative strategy.