8z. EL PLURAL DEL SUSTANTIVO. THE PLURAL OF NOUNS (Tema III, desde la página 27 hasta la pagina 33 de Gramática Inglesa para Estudiantes Españoles)

8z) Choose the correct form of the verb, singular or plural (Capítulo III, desde la página 27 a la página 33 de Gramática Inglesa para Estudiantes Españoles):

8z) Choose the correct form of the verb, singular or plural (Capítulo III, desde la página 27 a la página 33 de Gramática Inglesa para Estudiantes Españoles):
1. The aircraft (was/were) a small part of the advanced Soviet bloc weaponry
2. Linguistics (is/are) the study of the underlying principles of language
3. Measles (was/were) a common cause of death
4. Billiards (has/have) been played for many centuries
5. Physics (isn’t/aren’t) something I know a lot about
6. Those little crossroads (is/are) now growing out to meet each other
7. Its European headquarters (is/are) in Ireland and its Asian headquarters (is/are) in Singapore