13. That was the room_____ he once worked in.

13. That was the room_____ he once worked in.
a. which b. where c. when d. that
13题无疑问选a,后面定语从句he once worked in已经有介词in了，所以前面的连接词只用which即可。如果后面没有in就用where
14. i have forgotten the village _____ we once visited.
a. what b. which c. that d. where
答案是B或C．因为visit是及物动词，that /which 作关系代词引导定语从句在定语从句中作visited的宾语.

13. That was the room_____ he once worked in.
a. which b. where c. when d. that
选A
后面从句he once worked in已经有介词in了，所以前面的连接词只要which即可。如果后面没有in就用where或者in which

14. i have forgotten the village _____ we once visited.
a. what b. which c. that d. where
选B
visit是及物动词，用法是visit sp.不需要加介词，所以选which

13。 b,在从句中做状语成分
14。 c

that 不能选 因为前面的句子都是可数名词 而且还有the 限定

第一个选a 那是个定语从句 后面in
第二个选b 定语从句中动词是及物的 直接接名词 那就可以

13 a
14 b

13. b 14. c