We use pronouns/name+"的" to show the ownership. Examples: my car 我的车 our car & our cars 我们的车 your car 你的车 your car & your cars 你们的车 his car 他的车 her car 她的车 its car 它的车 their cars 他们的车 Kahliimah's car Kahliimah的车 Other examples: my book 我的书 a book of mine 我的一本书 This book is mine. 这本书是我的。

了≈simple past 过≈present perfect In reading, mostly you can follow this rule. In speaking or writing, pay attention to and imitate how native speakers use these two characters.

The more common way to say it's almost half past seven is 快七点半了。 If it's a little after 7:30, you can say 七点半多了。 And 七点半左右 or 差不多七点半 is ok for both.