Here are a few grammar questions that I've been asked this week:
1. Which is better: "like normal" or "as usual"?
You might hear people say "like normal", but it's much better to use "as usual".
2. What do "in order to" and "in terms of" mean?
A dictionary will explain the meaning of these phrases. However, it's probably more useful to see some examples of how they are used. A search engine like Google will give you many more examples than I can.
3. Is it correct to write "it is worth spending maintaining libraries" or "libraries are worth spending"?
Neither is correct I'm afraid. I would write: "It is worth spending money to maintain libraries" or "libraries are worth maintaining".
4. Can we put "for example" in the middle of a sentence like this: "There are many environmental problems, for example, people litter everywhere"?
The use of "for example" in the sentence above is not correct. To avoid confusion, I'd recommend using "for example" only at the beginning of sentences. Use "such as" in the middle (e.g. There are many environmental problems, such as air pollution).