Isthmi is plural. There are actually two plural forms. I will list them from singular to plural.
Isthmus - Singular
Isthmi - Plural
Isthmuses - Plural
The plural of isthmus is accepted as either isthmuses or isthmi.
An isthmus is a narrow region of land. When an isthmus connects two larger landmasses, it can be viewed as a natural path for land transportation or an obstruction for maritime transportation. Many isthmuses (or, if you prefer, isthmi.) are now cut by canals (Suez in the Sinai, Panama, Corinth) or have been considered for cutting (Kra, Tehuantepec...). Some of the USA's largest cities sit upon isthmi: Seattle and Madison, WI. So, Isthmuses Good: connect places, regions of commerce. Bad: Separate oceans/seas, transportation bottlenecks, Hipsters.
No, because there are not 100 plural pronouns.The plural pronouns are:weusyou (can be singular or plural)theythemthesethoseouroursyour (can be singular or plural)yours (can be singular or plural)theirtheirsourselvesyourselvesthemselvesbothfewfewermanyothersseveralall (can be singular or plural)any (can be singular or plural)more (can be singular or plural)most (can be singular or plural)none (can be singular or plural)some (can be singular or plural)such (can be singular or plural)
The plural of "she" is "they", so the plural of "she had" is "they had".
The plural of 'this' is 'these' and the plural of 'that' is 'those'.
The plural form is homes; the plural possessive is homes'.
The plural of rose is roses. The plural possessive is roses'.
The plural of 'bunch' is bunches.The plural of 'ant' is ants.The plural of 'batch' is batches.The plural of 'day' is days.The plural of 'chimney' is chimneys.The plural of 'tomato' is tomatoes.The plural of 'umbrella' is umbrellas.The plural of 'donkey' is donkeys.The plural of 'sky' is skies.The plural of 'foot' is feet.The plural of 'show' is shows.
applied is does not have a plural but is apply it does have a plural.
Knights is a plural. It is the plural for knight.
The plural is a regular plural, attics.
The plural form of can is cans.