Wring is to express your thought through language. Here we have to key elements: language and thought. For a successful writing activity to happen, both are necessary. When writing in our mother tongue, we spend almost no time in considering language, so our attention is mainly on contents. But when writing in a foreign language, we have to pay attention to both language and thought. If we cannot deal with these two, we might never learn to write in a foreign language well.
写作就是通过语言表达你自己的思想。这里面有两个要素:语言和思想。对于一个成功的写作行为来说,这两点缺一不可。在运用母语写作时,我们基本上不用花很多时间和精力去考虑语言,因而我们的重点是放在内容上。但是在学习用外语写作时,语言和内容就都需要注意。如果处理不好这两者之间的关系,我们可能就永远也学不好外语写作。

Generally speaking, learning to write in a foreign language demands you to go through three steps, although there is not clear distinction between them.
一般说来,学习外语写作有三个步骤,虽然这三个步骤是不能截然分开的。

First, learning the basic vocabulary and grammar of this language. At this time, learners have not grasped the basic usage, therefore are still in the basic stage of language learning. Writing exercise usually does not exit in this period; even if it does, it mainly serves a kind of vocabulary or grammar exercise. This kind of writing practice presents very simple contents, but requires that learners should use both vocabulary and grammar correctly.
第一, 学习这门语言的基本的词汇和语法。此时的学习者对这门外语的基本用法还未掌握,因此尚处于学习语言的基础阶段。这时写作训练一般没有,即使有也只是为练习词汇和语法服务。这种练习一般说来内容都非常简单,强调的是学习者所使用的词汇和语法必须正确。

Second, learning both language and thought expression. At this time, learners have already got familiar with the basic vocabulary and grammar, and can express simple ideas in this language. Writing exercises at this stage can work for two purposes. Firstly, they can help learners further their understanding of this language. Secondly, they can help learners express certain ideas in foreign language. In the learning practice, these two aspects are actually inseparable. Many students start to keep diary in English from Junior Three; they are in fact progressing in this second stage.
第二, 语言和内容并举。此时的学习者已经掌握了该语言的一些基本的词汇和语法,可以用该语言表达自己的简单的思想。这时的写作练习可以达到两个目的:(1)继续增强对语言的掌握;(2)用外语表达一定的思想。在具体的学习实践中,这两者实际上是不可分的。有许多初三的学生开始用英语记日记,其实他们就正处于这一阶段。

Third, learning to focus on thought. When learners can deal with the vocabulary and grammar of a foreign satisfactorily, and can use the language to express rather complicated ideas, they start to enter the third stage. Here language is no longer the biggest problem; instead, how to present good contents gains top priority. What learners pay attention to is how to choose their materials well, how to organize the ideas well, etc. Some people hold that only this third stage is really writing. This may be too biased. Writers, however, have to reach the third stage in order to be successful.
第三, 主要强调内容。当学习者对一门外语的词汇和语法有了一定的掌握,可以用它来表达相对复杂的思想时,就基本进入了第三阶段。此时的语言已经不是最大的障碍,如何写出好的内容成了头等大事。这一阶段的学习者所注重的是如何选材、如何组织文章之类的问题。有人说只有这第三阶段的写作才是真正的写作。这一说法可能失之偏颇,但成功的写作是必须达到这第三阶段的。

If you find it difficult to write complete sentences, you are still in the first stage. At this stage, you do not have to rush to long articles, although you may have some precious profound ideas in your mind. You should make efforts in language accumulation, paying special attention to usages of common words and sentence patterns. Besides, doing translation exercise may also help you improve your ability in using the language, thus making preparation for improving your writing ability. Many exercises in our translation column are also helpful in improving your ability in writing. What's more, doing more reading exercises can also help sharpen your sensitivity towards the language.
如果你发觉写出完整的句子尚有困难,这说明你还处于第一阶段。此时你不要急于写出长篇大论,即使你有些想法可能非常深刻。这时你应该做的是注意语言的积累,留意常用词和句型的用法。另外,适当做一些翻译练习也可以帮助你提高运用语言的能力,从而为提高写作能力做好准备。我们的翻译板块中有许多练习实际上对你们的写作能力的提高也是大有裨益的。除此之外,多做一些阅读,培养对语言的感觉也能为提高写作能力做一些准备。

To sum up, you may try to make efforts in these three aspects: accumulate language materials, try some translation exercises, and take up some reading exercises. As your language proficiency gradually improves, you will also gradually move into the second stage. Then you will have no trouble in producing complete sentences.
因此,你在现阶段可以从以下三个方面着手:积累语言素材、多做翻译练习、多做阅读练习。随着你的语言能力的提高,你会逐步进入第二阶段,到那时你就不愁写不出句子了。