1 . Two Chinese astronauts headed outside the nation’s Tiangong space station on February 9, 2023 for   ________ seven-hour-long spacewalk, ________ first of the ongoing Shenzhou 15 mission.

A．a; the

B．the; the

C．a; a

D．the; a

2 . In one experiment, Wang Yaping used a Bing Dwen Dwen toy, ______ popular mascot of ________Beijing 2022 Olympic Winter Games, to display how objects fly in weightless environment.

A．a; the

B．the; /

C．a; /

D．the; the

3 . He was on ________ phone when I paid ________ visit to him yesterday.

A．the; a

B．the; the

C．不填; the

D．the; 不填

4 . ---Annette has been complaining about_____ traffic keeping her awake at night.
---Yes, there is ________ heavy traffic on the road near the residential community.

A．/; /

B．/; the

C．a; the

D．the; /