The sun heats the earth, ___________ is very important to living things.

A. that              B. what             C. which             D. where

The sun heats the earth, __________ is very important to living things.

[    ]

A. that   B. what   C. which   D. where

The sun heats the earth, ___________ is very important to living things.

A．that              B．what             C．which            D．where

The sun heats the earth, ____is very important to living things.

A．that   B．which          C．what          D．of which

The sun heats the earth, _______ is very important to living things.

A. what　 B. which　 C. that　　 D. where

The sun heats the earth, ___ is very important to living things.

　　A. what B. that C. which D. where

The sun heats the earth, ______ is very important to living things.

[　　]

The sun heats the earth, ______ is very important to living things.

[　　]