题目内容：

阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

At present, Tech giants Apple and Google 1. (team) up to create a system that would let smartphone 2. (use) know when they’ve come into contact with someone who has COVID-19.The technology would rely 3. the Bluetooth signals that smartphones can both send out the receive. If a person tests positive for COVID-19, they could notify public health authorities through 4. app. Those public health apps would alert them anyone 5. smartphones had come near the 6. (infect) person’s phone in the prior 14 days. The technology could be used on 7. Google Android phones and Apple iPhones. The companies insist that they will preserve smartphone users’ 8. (private). The software will not collect data on users’ physical locations or their 9. (personal) identifiable information. Smartphone users must opt in to use 10.. People who test positive would remain anonymous. Google and Apple say their technology will be used only by public health authorities to trace the spread of COVID-19.