要 and 想

Question 1

What is the function of 想?

Answer 1

(a) to indicate a desire to do something

Question 2

What is the function of 要?

Answer 2

(a) to indicate desire to do something (neg. 不想), (b) to indicate intention to do something (neg. 不想), (c) to mean “to need objectively” (neg. 不用)