The extract below is from an essay written by a private student of mine. The topic is about the measures a college could adopt to make it more environmentally friendly.
Most of the colleges don't go further than the simple "paper" and "plastic" bins, which, in most of the cases, are not even in sufficient number to cover all the structures attended by students.
I am uncertain about the words in bold, should it be:
- are ... in sufficient numbers
- are... a sufficient number
- None of the above. The original is acceptable
Most...are... in sufficient number
The term number is usually singular when it precedes a countable noun; e.g., a/the number of bins, a/the number of colleges, but what if it follows the subject? Should number become numbers?
I could rephrase that particular section:
…the number of which, in most cases, is insufficient to cover…
But I would like to keep the word order and sentence structure as close as possible to the original.
Please help, I've been working quite a bit during the summer and my brain is totally fritto (fried), I just can't figure this one out.