Be careful when you deal with this chemical as it will explode when to sunlight.A. expos

问题补充：

Be careful when you deal with this chemical, as it will explode when to sunlight.

A. exposed

B. to expose

C. exposing

D. being exposed

答案：

(答案→)A. exposed

B. to expose

C. exposing

D. being exposed

解析：考查非谓语动词。本题考查短语be exposed to暴露与……。句意：处理这种化学物质时要小心，因为它暴露在阳光下时会爆炸。故A正确。