Since the gerund behaves as a finite verb form with respect to complementation and modification, it qualifies to form secondary predications. In this role, it is regarded as one of the means of complex sentence condensation. In a number of such cases, there is a theoretical possibility of replacing the gerund construction by a finite dependent clause. Detailed consideration of 175 potential clausal alternatives has shown that there recur certain problems that appear as blocking or obstructive factors having an impact not only on the actual process of replacement, but also on the resulting finite clause functioning as an alternative of the gerund. The limiting factors can be classified into several categories according to the linguistic feature which they involve, their frequency of occurrence and the extent to which they affect the actual replacement. On the other hand, they suggest certain qualities of the gerund which make it different from its potential alternatives and which can be fully exploited mainly in the construction of more complex sentences. Apart from the apparent reduction of the number of finite clauses, the gerund makes it possible to introduce into a sentence a range of various shades of meaning, semantic indications and nuances, and to make thus the language more flexible and capable of expressing complexity of thought.