Overuse of 'there are', 'it is', and related constructions
We all occasionally start sentences with There are, It is, etc. These constructions (in grammar we call them expletives) are useful when we want to emphasize information at the end of the sentence.
There are three reasons for continuing the experiment.
It is essential that we continue the experiment.
In these examples, the expressions inform the reader that some important information is about to appear.
But poor writers use these constructions too often. Note that as a subject and verb combination, 'there was', 'it will be', etc., tell the reader almost nothing. When used too often, they do not announce important information but instead only indicate a writer too lazy to find an informative subject and verb. Consider the example below.
example: There subject but not an actor are to be occasional cases in which the lion's attempt to capture prey is not successful.
This sentence is poor because the subject and verb of the independent clause (There are) are weak and convey no information. Also, the excessive use of 'there are' and 'it is' suggests a scholarly, bureaucratic style
revision: Lions subject and actor sometimes fail intransitive to capture infinitive preyhome