1 . The letter says the COVID-19 pandemic ________ (bring) great challenges to many aspects of the preparation work, and the committee has adjusted requirements for volunteers in consideration of virus control and prevention. （所给词的适当形式填空）

2 . A very beautiful town Bravuogn in Switzerland has banned tourists ________ taking photos in order to get holidaymakers(度假者)to take a break from social media. (用适当的词填空)

3 . Based on the psychology __________ creating a desire to buy, advertisers have developed ways of persuading people into purchasing their products or services. (用适当的词填空)

4 . I used to get high marks in English, ________ now I'm having a lot of trouble with my listening. (用适当的词填空)