Choose the right grammatical form in each gap to complete the text

Today you can hear a lot about the reduce, reuse, recycle system which aims to help people understand how to live a more eco-friendly life. If you have never tried doing anything like that,[will be|don't be|should be|could be]afraid. You can start with something simple like buying a reusable bag instead of using plastic bags each time you go shopping. Try to avoid impulsive purchases when you suddenly see something and decide to buy it even if you[wouldn't|don't|didn't|hadn't] need it. This is why you'd better have a shopping list every time you go to a store. If you already[have|had|hadn't|will have]too many things you don't need, like clothes, for example, don't just throw them away. Firstly, you can share with people in need or donate good clothes to shelters and funds. Secondly, you can try to sell things if you want to earn a bit. Besides, if you[were|was|are|will be]fond of DIYs and crafting, you can give your old clothes a second life. There are lots of ways to make bags, cushions, carpets, toys and more things out of the old fabric. If many of us[know|will know|have known|had known]all these tricks earlier, we[would have thrown|wouldn't be throwing|couldn't have thrown|couldn't throw]away so much.