It's {#blank#}1{#/blank#} {#blank#}2{#/blank#} {#blank#}3{#/blank#} to do it.

{#blank#}1{#/blank#} {#blank#}2{#/blank#} a {#blank#}3{#/blank#} {#blank#}4{#/blank#}?

⑴at 7:00{#blank#}1{#/blank#}          A. at seven forty

⑵at 7:20{#blank#}2{#/blank#}          B. at six forty

⑶at 6:40{#blank#}3{#/blank#}          C. at six thirty-five

⑷at 6:35{#blank#}4{#/blank#}          D. at seven o'clock

⑸at 7:40{#blank#}5{#/blank#}          E. at seven twenty

—{#blank#}1{#/blank#} {#blank#}2{#/blank#} {#blank#}3{#/blank#} {#blank#}4{#/blank#}? 
—No, {#blank#}5{#/blank#} {#blank#}6{#/blank#}.