Final answer:
The phrase 'my friend or I' in the question is a compound subject because it combines two subjects with the conjunction 'or'. It is not a compound predicate as the predicate 'help clean up' is singular.
Step-by-step explanation:
In the sentence 'Can either my friend or I help clean up?' the phrase 'my friend or I' acts as a compound subject, because it's combining two subjects (my friend and I) with the word 'or.' This is not a compound predicate because the predicate, which is the part of the sentence telling what the subject does or is linked to (in this case 'help clean up'), is not combined with another predicate.
In English grammar, a compound subject contains two or more simple subjects that are usually joined together by a coordinating conjunction, such as 'and' or 'or', and share a common verb. The rule of subject-verb agreement states that when compound subjects are connected by 'or,' the verb should agree with the subject that is closest to it.
For example, in the sentences 'Either your uncles or your mother remembers your grandmother's gumbo recipe.' and 'Either your mother or your uncles remember your grandmother's gumbo recipe.' the verb 'remembers' agrees with 'mother' and the verb 'remember' agrees with 'uncles' because they are the subjects closest to the verb, respectively.