1. I am writing an English exercise now.
2. I was writing an English exercise at this time yesterday.
3. My little sister is sleeping now.
4. My little sister was sleeping at this time yesterday.
5. My friends aren’t doing their homework now.
6. They are playing volley-ball now.
7. My friends wasn’t doing their homework at seven o’clock yesterday.
8.They weren’t playing volley-ball at this time yesterday.
9. I was eating an ice-cream when you rang me up yesterday?
10. What your father is doing now?
It is necessary to be able to speak English nowadays because it's the most commonly used language among foreign language speakers. If you know English, you can contact people from all over the world. English is the most common language used on the Internet (just think of all those popular social media). Moreover, English is now the global language of business, so a good level of English gives you better job opportunities.
In order to improve my knowledge I listen to songs, read books and watch films in English. When I have free time I surf the Web and do all kinds of language tests. I also listen to podcasts in English. Joining online English forums is a great way to practise the language. I like playing computer games so I have joined a gaming community forum with participants from all over the world and we all post our messages in English.
I would like to learn Spanish and Mandarin Chinese because they are also widely-spoken languages in the world and most people believe that Chinese, English and Spanish are the languages of the future.