试管婴儿技术又叫体外受精技术，从技术层面上说，到目前为止已出现了三代“试管婴儿”。第一代“试管婴儿”是指通过常规的体外受精和胚胎移植技术，知道临床妊娠分娩；第二代“试管婴儿”是指通过显微人工受精技术，帮助精子通过透明带或穿过卵细胞膜，直至临床妊娠分娩；第三代“试管婴儿”是指胚胎着床前进行遗传学诊断，剔除带有遗传病的胚胎。对于那些因输卵管堵塞等原因而导致不孕的问题，试管婴儿提供了一个很好的解决方法。但试管婴儿技术也存在一些严重的缺陷。研究表明，任何针对卵子的外在行为都会对其造成一定的伤害，同时人为导入的精子本身可能存在异常，从而使死胎、新生儿死亡率及异常胎儿的比例明显上升。

根据短文内容回答下列问题。

Round the World

    Mr and Mrs Spencer both had very busy jobs and didn't have much time to spend with their young children. They wanted to change this, and because their hobby was boating, they decided to sail round the world together.

    It took six years to prepare everything for the trip. First, they bought a new boat. Then, both the husband and wife had to take advanced(先进的) sailing lessons and learn all about the sea and the weather. Mr Spencer also did several courses in repairing engines and Mrs Spencer spent an hour in a restaurant learning to cut up fish.

    In October, they had one year off from their jobs and sailed away from England with their two children. The next year, in August, their long journey ended in Australia.

    The boat was not big, but they took a teacher for the children with them. None of them found the trip boring because there were three computers, many CDs, a TV and a DVD player on the boat.

    The family loved being at the sea and seeing the stars in the sky. But, most of all, Mr and Mrs Spencer enjoyed spending time with their children while they were still young.

假如你穿越时光，来到两千多年前的秦王朝，你不可能看到的情景是（　　）