Perhaps a clearer, more practical way of describing this subject-verb peculiarity of inverted sentences is as follows: if the subject and predicate of a sentence differ in number, the binding verb corresponds to the number of substantive sentences on the left. The normative phrase “What I need is two returns to Puerto Princesa”, that is, conversely, “Two round trips to Puerto Princesa is what I need.” Even if it is not a sentence inversion, we must keep in mind that this rule of subject-Verb English correspondence normally applies even if the subject and predicate of a sentence are both in the form of substantive sentences (unlike nouns or autonomous pronouns) and when they differ in number or person. In such cases, the form of the binding verb “be” corresponds to the previous substantive sentence – the one on the left in the sentence – even if that substantive sentence is logically not the subject. . . .