-----Do you know we’ll get there at 3:00 this afternoon?-------I’m afraid we’ll be late.a

问题补充：

-----Do you know we’ll get there at 3:00 this afternoon?

-------I’m afraid we’ll be late.

a. that b. how c. why d. if

答案：

解析：此题考查宾语从句的引导词的问题，根据语境可知用if。