1. Use "neither," which is dual, like "both." 2. The word "each" is considered to be singular, so use "each is." alternatively, you can rephrase this sentence as "all of the books are...."

Are you both from America? No, none of us. this is an incomplete sentence and normally you would use neither here Are you both from America? No, neither of us are. none is more commonly used with a larger number example : is anyone in this room from the states? Nope, none of us are from the states. Each of the story books are very interesting, so I can't decide which one to choose is is a singular pronoun and are is for plural(many). I'd personally use "all of these story books are very interesting, so I couldn't decide on which one to choose" since you used "so" here it suggests the dialog is after your thought so you would use past tense here.(couldn't) "each of" can be used in this context but it might be better if you added a few more words to complete the sentence example:"Each of these books have very interesting stories and I can't decide on which one to buy" using"and" as conjuncture make it present tense as you are thinking while the dialog flows alot of these comes from practice and talking to people. otherwise you'd have to study grammar hard. heck, I might've made careless grammar mistakes here so feel free to point them out