1.相反的，少数学生似乎还在虚度光阴。 On the contrary, a few students, it seems, are still fooling around.
2.政府应严格执法，另一方面，大众也应该培养减少污染的好习惯。
The government should enforce laws strictly. On the other hand, the public should also develop the good habit of reducing pollution.
3.换言之，我会尽最大的努力达到我的目标。
In other words(To put it differently), I will try my best to attain (gain; live up to) my goal.
4.从此之后，我已发现微笑是避免我们日常生活中发生纠纷的最好办法。
Ever since then, I have found that smiling is the best way to avoid any possible conflicts in our daily life.
5.更严重的是，我们不珍惜野生动物。 What is more serious is that we do not cherish wildlife.
