设$a\in R$，则“$a=1$”是“直线$l_1;ax+2y=0$与直线$l_2;x+\left(a+1\right)y+4=0$平行的（ ）

青藏地区的农业，主要分布在（　　）

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(____) What are those?

(____) Wow! You have a lot of animals! Are they sheep?

(____) Let me count. Mmm…Fifteen. Look, they are cows and hens.

(____) They're horses.

(____) Look! This is my farm.

(____) No, they aren't. They are goats.

(____) How many horses do you have?

(____) Your farm is so big. I like it.