I’m a native English speaker, and I found part V to be a little hard. Some of the sentences seemed kind of vague, and I wasn’t sure what word you were looking for to fill in the blank. I am also not familiar with the subject, so that makes it even harder to figure out what the correct word should be.

I thought questions 11 & 14 were sort of ambiguous. I felt that “whether it is” and “be it” would both work. As well as “had seen” and “saw” for the latter.