What is the plural of that is a bianck knife
Those are black knives.
The complex number of knife
For example, leaf becomes leaves, thief becomes things, and life becomes lives
Which word is plural, Japanese or Japanese
Japanese is both singular and plural. It is a word with the same form of singular and plural. Some words ending with ese that indicate the country or the people of which country are also with the same form of singular and plural, such as Chinese