Hi,
I will bring up some critiques...
First of all, such topics on TOEFL ask you to choose only ONE side and then bring supporting arguments.
You, unfortunately, have failed to do so. As a result, you lost at least 1 point from the maximum score.
yui_2000
Some people prefer to work on only one task at a time. Others think multitasking is a better way to get more work done. Which do you prefer and why? Give specific reasons and examples to support your answer.
No doubts that we live in competitive environment nowadays. The environment (I believe THIS is more appropriate, as you refer to the competitive environment that you mentioned in the preceded sentence) requires that people should (require is a subjunctive mood verb - never ever use SHOULD with subjunctive verbs, as it is 100% incorrect) work more effectively, so they need to find a better way to get work done. Many people think multitasking is an answer (answer to what? you need to show a smooth transition from one idea to another); however, others like to stay focus on one task at a time.
Working on one task at a time (same wording repeated with only one word in between - not good) is a good method because it’s relaxing. When we pay attention on TO (correct preposition is TO) only one task, we have enough time to complete it. There is nothing to hurry us, and we enjoy the work that we are doing. For example, I only need to learn a poem by heart at a time. I feel it’s easy, and I want to complete this task early to take next task. So (never start a sentence with FANBOYS - for/and/nor/but/or/yet/so - these are conjunctions that connect two independent ideas into one sentence) this method makes us feel calm and relaxed.
Multitasking, meanwhile, is the opposite of relaxation. When we have too many things to do at once, such as doing math, checking email, and chatting with friends (I would recommend not including this info at all...as it is not a work related thing...) , it distracts ( what exactly distracts? you mentioned several things..) and make we US feel that it is impossible to finish all these works (work is an uncountable noun - it does not have a plural form). This (does not have a clear antecedent) causes stress, so it is an awful idea to do a lots of things at once. If people want to relax while they work, they will want to do only one task. Thus, working on one task at once is a better choice in work situation. (I would recommend changing the whole underlined part - sorry for pointing out, but relaxing while you work, it doesn't seem real)
As a result, working on one task at a time is an important method to help people work effectively. Although there are many people who take comfort in multitasking, I, personally, prefer working on one problem at a time. With this method, I will love my work and spend more time on working.
I know that it takes some time to develop your writing skills. Go through your mistakes, and make sure that you do not make them again.
Considering all above said, I wouldn't give you more than 3 for your essay.