1 . As the intelligent species, the human personality lies within the mind and body, ________ existence we had only recently become aware.

A．of which

B．of whose

C．of whom

D．of its

2 . David donated a large sum of money and some necessities to the charity, _________he received a heartfelt letter of thanks from the organization.

A．for which

B．with whom

C．about whose

D．in where

3 . Volunteers in China, _______ are playing an increasingly important role in many fields, are actively participating in the battle against COVID-19 at present.

A．which

B．that

C．who

D．where

4 . My mother was too busy to remember my birthday, ________ made me a little upset.

A．which

B．that

C．whom

D．what

5 . It is this book, with ________ help you have deepened your understanding of Chinese culture, that is worth reading.

A．which

B．that

C．whom

D．whose