题目1：有些网络乡民一旦进入虚拟世界就无法离开电脑(.....have defficulty.....)
Some netizens have difficulty walking away from their computers
once they enter the virtual world.
题目2：虽然这场演唱会的票很贵，但它们还是一天内就销售一空（......as.....)
Expensive as the tickets to the concert were, they were still sold out
in one day.