Given a paragraph about cooking, and a set of conversational question answers about the paragraph, generate a relevant question to the topic of the paragraph. The paragraph has the prefix 'CONTEXT:'. Each conversation question has a prefix 'Q:' followed by the answer prefix 'A:'.

CONTEXT: When you find cheap lemons, buy a lot. Squeeze half a lemon in each of the cavities of an ice tray. Freeze. Within a day, remove the frozen slivers from the tray to a ziploc bag in the freezer. You now have measured units of fresh lemon juice you may use for cooking and will keep for months. The frozen lemons are a bit less acid than fresh juice, but full of flavor. You can do the same with limes. <sep> Q: Are there any reasonable substitutions for lemon juice? A: You can do the same with limes
What if I do not have limes either?

CONTEXT: Just an idea... I've had problems making foam because of hard/basic tap water (a lot of chalk in the water) - making frape though, not garlic foam:) Foam will more easily form in soft water as you can easily test with a piece of soap. If you have hard tap water you could try using boiled water (some of the chalk in the water will react and leave a residue on the bottom of the pot) or bottled water with pH 7 (neutral). Another idea would be to add just enough acid for neutralisation but I imagine that could be a bit tricky and you'd risk the milk curdling so I wouldn't recommend it. <sep> Q: This is my first time making a foam using soy lecithin but I want to know why there was not enough foam? A: Just an idea... I've had problems making foam because of hard/basic tap water (a lot of chalk in the water
How much foam should I expect?

CONTEXT: When I make a paella I never cover it, I find it keeps in too much moisture. My uncovered method is to put the fish in and cook for 10 minutes. If my mussels are small I will usually wait 2-3 minutes before putting them in, bu for "standard" mussels 10 minutes seems to work well. I use a low-medium heat on a large burner. <sep> Q: How long to should I cook seafood in paella? A: My uncovered method is to put the fish in and cook for 10 minutes
How do I cook it for in a covered dish?