English for Writing Research Papers

6.3   -ing form vs. that
Authors sometimes use the -ing form in what is effectively a relative clause (i.e. a 
clause that begins with that, which or who - see Sect. 
6.1
). This usage is acceptable 
in phrases such as:
 
S1.  Those students wishing to participate in the call for papers should contact …
 
S2.  The professor giving the keynote speech at the conference is from Togo.

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6.4 - ing form vs. subject + verb
S1 could be rewritten as students that / who wish, and S2 the professor that / who 
is  giving
.  However,  there  is  no  possible  ambiguity  because  the  -ing  form  comes 
immediately after the noun it refers to.
However, in S3 it is not clear who has the good level of English: the students or 
Prof. Rossi.
 
S3.  * Professor Rossi teaches the students having a good level of English.
S4 clarifies that it is the students that have good English. In S5 Prof. Rossi is the 
subject of both verbs (teach, have), so in this case we need to change the structure 
of the sentence and use since, because or something similar.
 
S4.  Professor Rossi teaches the students that have a good level of English.
 
S5.  Professor Rossi teaches the students since he has a good level of English.