1 . I never forget this summer vacation, ___________I spent the happy days with my friends.

2 . I didn't become a serious climber until the fifth grade，________ I went up to rescue a kite that was stuck in the branches of a tree. (适当形式填空)

3 . Mr. Smith owned this oil painting until the early 1990 s, ____________he gave it to his grandson.

A．which

B．when

C．where

D．who

4 . Between the two parts of the concert there was an interval, _____ audience can go and buy some snacks.

A．where

B．when

C．how

D．why

5 . We live in the age of distraction, ______ we can be disturbed by all of kinds of useless and false information.

A．which

B．what

C．when

D．where

6 . 5G commercial service’s being officially launched has opened a new digital age, ____ not   only technology but also people’s work capacity and lifestyle will be upgraded.

A．as

B．where

C．when

D．which

7 . 阅读下面材料，在空白处填入适当的内容（1个单词）或括号内单词的正确形式。

last Thursday,   there was a   big fire in a big shop in our city. At 8:16 that morning,    1     the employees were working   busily in the 4-storeyed building, heavy smoke was seen     2     (come) out of the windows on the second floor. The fire lasted nearly an hour, and the majority of the 345 employees managed     3     (escape) from the fire. Unfortunately, 7were killed, and 23 injured, lightly or seriously.

Some workers     4     (complain) that aids came too late,     5     the firemen did come just 10 minutes after the fire was reported. To rescue everyone from the burning and smoking building in such a short time was too difficult. The only two exits of the big building were not enough for so many people to withdraw in    6    hurry.

The reason of the fire, according to an investigator, was       7     someone broke the non-smoking rule in the factory, because some cigarette   ends     8       (find). Next two weeks, 15 inspection teams will be working in all the factories     9     turn, aiming to clear away the possibility of more fires.     10    (hope), no disasters like this will happen again.

8 . We will put off the picnic in the park until next week, ________ the weather may be better.

A．that	B．where
C．which	D．when

9 . I didn't become a serious climber until the fifth grade, _____ I went up to rescue a kite that was stuck in the branches of a tree.

A．when	B．where
C．which	D．why

10 . Between the two parts of the concert is an interval, ________ the audience can buy ice­cream.

A．when	B．where
C．that	D．which