(1)Youcandependon_____allthegoodswillbedeliveredintime.
A.thatB.whetherC.itthatD.if
(2)Itwasfouro'clockintheafternoon______heandhisteamreachedthetopofthemountain.
A.whenB.thatC.whereD./
请帮助选择两题各自的正确答案,并且能从语法角度说明一下.