Answers.
01. There is no one watching TV because there are no good programmes on.
02. There is a cat in the kitchen because there are mice in there.
03. There are a lot of policemen about because there is a political demonstration today.
04. There is a queue at the department store because there is a sale on.
05. There are no complaints because there is good service.
06. There is no hot water because there is a power shortage.
07. There is no swimming today because there is no water in the pool.
08. There is a lot of work to do because there is a new manager in the office.
The same sentences can now be read in the past tense: "There was... There were..."