is this sentence OK？ G

are circular or to be circular for the sake of simplicity, we have assumed all (the) pneumatic channels are circular/ to be circular.

at very first time; at the very first time; at very the first time ; which is correct ? In 2014, Lauder research group at Harvard University, for very the first time, successfully manufactured flexible bio-mimetic shark skins

corresponds or corresponding The surface morphology, usually corresponds/corresponding to the mechanical instabilities, could be determined by the theory of solid mechanics.

Rather than DO or DOing A well-known application of dimpled drag-reducing surface is golf ball, which have about 250-400 dimples on the surface rather than have/having a smooth surface. Could I use 'have' or 'having' in the sentense? Thanks for your time.

IELTS Writing task 2. Why children are unhappy? In some countries, many children are unhappy. What are the reasons? What can parents and schools do to solve this problem? Over the past 20 years, socialists have been increasingly aware that many children appear to be unhappy with their life in some countries. In this essay, I will take my country-China for an example to explain why this situation happens and which measures should parents and schools take to deal with this issue. An initial reason for the unhappiness for children is the much heavy studying burden. Children in developing countries like China are experiencing increasingly high exam stress in order to enter a college since China’s educational resources are still in shortage. A lot of children have to attend exam training courses on weekends, which occupy their leisure time. Another possible reason is the case that many children in urban areas feel lonely. They usually live in separate communities and thus have little time to spend together after school. Parental company plays an major role in children’s happiness. Parents should spare ample time to spend with their kids, paying heed to what they are saying but without judging them. Adults should also teach their kids about how to build friendships with their peers. In addition, schools should respect children’s privacy, for example, tutors do not rank their students by exam results, which would have a negative effect on students’ confidence. Schools or educators could also organize high quality class activities regularly to boost the friendships among classmates. In conclusion, heavy exam stress and the lack of friends are two main reasons why children feel unhappy. To solve this problem, I personally believe that parents should pay much more attention to their kids and work together with schools to assist children build friendships with peers.

IELTS writing task 2. New technologies or free education? Some people think that governments in developing countries should introduce new technologies   to people  in order to improve the quality of life, while others believe that in order to achieve that  governments should  offer free education for all. Discuss both these views and give your own opinion.  It is a crucial social issue in terms of how to improve the life quality of people who are living in developing countries. Some scientists suggest that governments should import new technologies while some educationalists reckon that providing free education for the public should be a better way. I personally tend to agree that both advice sounds reasonable but the former one seems to be more viable and practical. People’s daily life invariably benefits from new technologies. For example, governments could import modern public transport systems like urban rail transit and rapid bus transit to provide cheaper and more comfortable seats for city commuters, and thus tackle traffic jams in the urban area. For those who are living in rural area, the local communities and governments may introduce modern agricultural techniques such as fertilizers and irrigation systems to help farmers produce much more crops and grains. This would contribute to reducing the living cost in the rural area. In addition, new clean and sustainable energy technologies like nuclear energy and solar energy should be adopted to reduce the consumption of coal and petroleum, serving to solve the growingly severe air pollution problems in developing countries. Providing free education for the public would also help. Expectedly, an individual who has been well trained and holds a higher degree would have more chance to find a better job. However, given the limited budget in developing countries, this policy seems to be less realistic. In conclusion, although free education for the public seems to be useful to improve the literacy level in developing countries, innoviative technologies could directly prompt the developing in cities and rural countries, which would increase the life quality of people.(281 words)