I am writing a thesis in English. After finishing, I used two grammar-checking software programs to pick up grammar errors. However, confusing results for a sentence were given by the two applications.
The original sentence is as follows:
There have been a large number of studies investigating…
One application tells me there are no mistakes in this sentence; however, another one suggests that a singular verb ("has") should be used. I searched for similar sentences in the corpus; however, both of them ("has" and "have") were used for "a large number + plural nouns" in some newspapers and magazines.
Would anybody help with this? I really don't know which one is right.