The bus that pulling up outside the inn wpuld soon take the visitors downtown.
问题描述：
The bus that pulling up outside the inn wpuld soon take the visitors downtown.
答
1. pulled up
2. is pulling up
3. was pulling up
都可以.
第一个表示情况（巴士的到来）已结束,
第二个表示事情还在进行中,
第三个是叙述形式的过去进行时.