题目

完形填空，通读下面的短文，掌握其大意，然后从各小题所给的四个选项中，选出一个最佳答案。London has some fantastic sights for every tourist. But just    1    back does this wonderful city’s history go? It was the Romans who decided to build the city we know today as London. They invaded (入侵) Britain in AD 43, and soon afterwards built the city of Londinium. They saw that a city with a bridge    2    the Thames River could be useful, both for traveling to Europe and traveling in England. It is thought that the original city was small —我校在教学楼旁挖一个棱长4.5米的正方体蓄水池，现要将它的四周和池底都抹一层水泥，抹水泥的面积是多少？