True or false, an implicitly unwrapped optional variable must have an exclamation mark affixed after it every time it is used. 答案选项组

How can a user delete a drawing object

Before you record your own voice, you should a. record other people's voices b. warm up and practice difficult names c. listen to your favorite songs d. read a transcript of a good radio news segment

Me dangers of social media and the internetexplain what each means: 1) social media and phones have become an addiction.2) outside people have access to you all the time.3) cyberstalking4) cyberbullying5) catphishing6) viruses7) identity theft8) credit card fraud9) hacking10) money schemes