Generally speaking, putting objective information at the beginning of a sentence (so that it occupies the place normally reserved for the subject), unintentionally adds emphasis to that information. You can highlight a topic in English, but this should be done by using a special ‘fronting’ device. If we take the example below, we could emphasize matter in the following ways:

Regarding that matter, I am responsible.

Or

With regard to that matter, I am responsible.

You cannot use devices like concerning or for as in:

7 Concerning my written assignment, it is very difficult.

And

7 For some written assignments, they are very difficult.

These constructions are not acceptable English. They sound too strong. Delete the device, comma and pronoun to produce:

My written assignment is very difficult.

And

Some written assignments are very difficult.

You should note that introducing a topic with for is not always unacceptable. For example:

For many people, summer is the most enjoyable season.

But it would be wrong to express this as:

7 For many people, they find summer the most enjoyable season.

There are other way in which you may unintentionally topicalize. For example:

7 Take too little exercise, it is dangerous to health.

Remember, in English, you cannot begin a statement with a pure verb form because a verb cannot occupy the sentence-initial (subject) position. You could use a non-finite verb form, however, since this functions as a noun and can, therefore, be placed in normal subject position at the beginning of the sentence:

Taking too little exercise is dangerous to health.

You could instead begin with a personal subject:

You will endanger your health if you take too little exercise.

Or with an impersonal (dummy) subject:

It is dangerous to health to take too little exercise.

Another way of satisfying the requirement of English to have the subject position adequately occupied is to use the dummy one (although this is rather old-fashioned now):

One will endanger one’s health if one takes too little exercise.

Note the repetition - use one sparingly.