a. Even though I usually know what I have to say, I cannot always express myself correctly in English.
b. This challenges me to practice my spoken English, with the result that I can complete the speaking tasks more fluently and quickly.
c. I think this is less than ideal because any differences in opinion become personal conflicts, and therefore that might jeopardize the employee’s job.
d. Shallow writing is indicative of weak critical-thinking skills, and such writing, which is often described as “sophomoric”, receives low mark.
破碎句：She singing alone.（无谓语，singing是现在分词）
正确句：She is singing alone.
破碎句：He did not come. Because he was sick.（从句独自成句）
正确句：He did not come because he was sick.
连续句: Professionals such as lawyers or accountants usually work longer hours than factory workers they have greater freedom in planning their time.
正确句一: Professionals such as lawyers or accountants usually work longer hours than factory workers. However, they have greater freedom in planning their time.
正确句二: Professionals such as lawyers or accountants usually work longer hours than factory workers; however, they have greater freedom in planning their time.
不正确句: Breaking chalk into two pieces is a physical change, there is no change in the composition of the chalk.
正确句： Breaking chalk into two pieces is a physical change, so there is no change in the composition of the chalk.
正常句： Luck only works in extreme cases.
倒装句： Only in extreme cases does luck work.（否定词位于句首的倒装。）
正常句： The internet provides people access to the latest information.
着重句： It is the internet that provides people access to the latest information.（着重the internet）
正常句： The environment has been deteriorating severely along with the development of industry.
状语前置句： Along with the accelerating development of industry, the environment has been deteriorating severely.
正常句： However, new zoos try to duplicate animals’ natural habitats as much as possible and give animals a comfortable amount of space.
插入语： New zoos, however, try to duplicate animals’ natural habitats as much as possible and give animals a comfortable amount of space.（连词however做插入语）
She suddenly had an idea.
An idea suddenly occurred to her.
He was absent-minded when driving, and almost caused an accident.
His absence of mind during driving nearly caused an accident.
The United States of America was founded in 1789.
The year 1789 witnessed the founding of the United States of America.
1. It pays to make great efforts to prepare for TOEFL-ibt.
2. Nothing is more important than to receive education.
3. The reason why the white-collars suffer increasing work-related stress is that they pursue work achievement in career.
4. It is time the related department took proper measures.