Past continuous or Past simple

Jack ​ (a)   while I ​ (b)   TV.

• arrived
• was watching
• was arriving
• watched

When the taxi ​ (a)   we ​ (b)   in.

• arrived
• got
• was arriving
• were getting

It ​ (a)   snowing while we ​ (b)   the mountain.

• started
• were climbing
• was starting
• climbed

He ​ (a)   on his computer when I ​ (b)   him.​

• wasn´t playing
• saw
• didn´t played
• was seeing

​ (a)   when she ​ (b)   the accident?

• Was she skiing
• had
• She skied
• was having

I ​ (a)   ​ he had a problem when I ​ (b)   him shout.

• knew
• heard
• was knowing
• was hearing