The teacher propose that Jack maths or physics instead of English because he was quick at

问题补充：

The teacher propose that Jack maths or physics instead of English because he was quick at numbers.

A. must study

B. could study

C. studied

D. study

答案：

A. must study

B. could study

C. studied

(答案→)D. study

解析：考查情态动词。propose引导的宾语从句，谓语动词应用should+动词原形，故答案为D。