A number of papers have suggested alternatives but unfortunately none of them were satisfactory. = The alternatives have been tested and proven inadequate. A number of papers have suggested alternatives but unfortunately none of them are satisfactory.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
AnonymousA number of papers have suggested alternatives but unfortunately none of them have been satisfactory.No. Because someone might read it as the papers were defective. The ambiguity comes from the parallelism in tenses: "papers have suggested" and "none have been satisfactory."