有一读者问： 有这样一句话：
(1)In 1895 she married Piere Curie, a very bright scientist who had teaching at the School of Physics and Industrial Chemistry at Paris.
问为何不用in Paris而用at Paris?
一般说来，较大的地方前常用in，较小的地方常用at。但如强调位置或地点而不强调空间，较大的地方亦可用at，再如：
(2)They were marching straight toward the wooden bridge which spanned the river at Rome.
(3)Dr. Chen, chief of the orthopedic department of the No. 6 People's Hospical at Shanghai, demonstrated it to us.
在下面两种情况下，较大的地方之前也常用at：
(4)We stopped at London on the way to New York. （这里显然将London看做路过的地理上的一点）
(5)Thackery was not born in England but in India——at Calcutta. （Calcutta虽然是一大城市，但小于India，故Calcutta前用at, India前用in）
