【问】 To see how slow he drove，you must run slow along with the car.
 上句中的how slow he drove和run slow，其中的slow都用作副词，为什么C(run slow)却是错误的?
 【答】 slow和slow ly都可用作副词，但是slow用作副词是有一定限制的。主要与go，drive和pass连用：
 1.Danger，go slow.(路标警告用语)
 危险，慢行。
 2. Drive slow!
 开慢点儿! (慢开!)
 3. You are going too slow. (EED)
 你走得太慢了。
 4. Go slow through the village. (Palmer)
 慢慢地通过村庄。
 5. The car went slower and slower until it came to a standstill. (Wood)
 车子越开越慢，终于停下来了。
 6. How slow he drives! (LDCE)
 他开得多慢!
 另外，还用于成语go slow(慢慢干，怠工)
 1. You ought go slow until you feel really well again. (OSD)
 你得慢慢来，直到你真的感到你恢复了健康。
 2. All our mail is being delayed as the postal workers，are going slow. (Chambers)
 我们所有的邮件都被耽误了，因为邮政工人正在怠工。
 即使如此，还是有人主张使用drive slowly：
 He drove the car slowly into the garage. (CGEL)
 他慢慢地把车开进车库。
 上面试题的出题者显然是主张drive slow是可以接受的，而run slow是不可以接受的，应改为run slowly。