What's the main difference between "harassment" and "abuse"?

When does the word "film" be used as an uncountable noun? I thought if "film" is countable noun if it is referring to the video that is captured and visible.

"Film" is considered both a countable and uncountable noun. You are also correct about the definition of film: "film" is referring to a video/movie that is captured and intended to be watched by viewers. However, you can use "film" when referring to more than one. "Film" and "films" are used to indicate more than one film. Here are examples of "film" and "films" being used in a plural context. Ex: We have different film on health in our library. Ex: We watched several films on safety for work training. Ex: They went to the film festival last year. Ex: I watched a horror film last year.

What is the difference between "back" and "backward"?

In this context, to "look back" and "look backwards" actually have the same meaning. "Back" describes the position of something, and "backward(s)" is used to describe the movement of something that is moving back. To "look backwards" means to look at something that is behind you, but it is not usually used in the metaphorical sense as often as "look back" is. For this reason, the sentence spoken by Steve Jobs in the video is slightly awkward. "But it was very, very clear looking back 10 years later" is actually a more natural way of expressing the action of reflecting upon past events. Ex: Looking back on my youth, I achieved more than I thought I did. Ex: There was a shout behind her. She quickly looked backwards.

Unlike other accents, I think I've seen many comedians are making fun of Texan accents in their show. Why is that?

I'm not 100% sure. However, I would say that the Texan and southern accent is one of the most fun and distinguished accents to do. There are also a lot of stereotypes and generalisations of Texans that are easy to make fun of. Here are a couple of examples: Ex: Everybody in Texas listens to country music. Ex: In Texas, chicken is a vegetable unless it's fried.

What's the difference between "hold on", "hang on" and "Just a minute/second"? Are they always interchangeable?

These expressions have similar meanings and are usually interchangeable in situations when you'd like to tell someone to wait a moment. "Hold on" and "hang on" also have additional definitions, however, as they are used to also mean "stop" or "wait," and also as encouragement to persevere or endure in difficult situations. In this video, "hold on" is closer to the last definition, meaning for Bill to endure or persevere until he can get help. Ex: Just a moment, I will help you as quickly as I can. Ex: Hold on, you're driving too fast! Ex: Hang on for just a little while longer, the exam season will be over soon! Then you can finally have a break.

When can I use the word "heartbroken"?

The word "heartbroken" means to be very distressed or upset over something. You can use the word "heartbroken" when discussing a breakup, an unpleasant situation, or even death. Ex: She was heartbroken from her father's death. Ex: I never felt so heartbroken. I loved him. Ex: We were heartbroken when our dog died.