Practice 1

This company has showed us significant growth during last 5 years. However, since the current two quarters, it seems that the company's net profit has been decreasing. We expect this (these) figures came from decreasing sales. Market demand trend seems that customers do not want to purchase our high-quality products, rather than, they choose cheaper ones. The gap between cheap models and premium models has reduced. There is no more merit buying premium models with paying more costs to customers. (This entire sentence sounds weird. I'm not sure what you're trying to say).
What the company should do now for the future? (You should either take this out or change the way it is phrased to "What should the company do now for the future?"). Experts say the company had (change to "has") to develop their own software, but they have outsourced by(to) another company so far. It is all expenses every product they are selling.(This sentence doesn't make sense. Maybe change it to, "The company is wasting more money this way.") If they have strong and competent software for products, (You don't need a comma here) they could save money by not paying a patent fee to another company,(change comma to a period to start a new sentence.) also(Also,) they are able to sell it to competitors as well.
It is time to think about sustainable growth. The company is still making a lot of profits but it won't be forever. Historically, many succesful companies vanished when they did not pay attention for(to) the future, when they hesitated changing their system and structure. We should learn from it.

Good job overall though!