用所给单词的适当形式填空。
I can ____ (sit) down here and have a rest.
张兵在“测量石块的密度”的实验时，测出几组数据，根据这些数据绘出图像，能正确表示“密度与质量的关系”的图像是( )
属于体液而不属于内环境的液体是
A：Wow! What a great model plane! Is it yours，Jack?
B：Yes，it's mine．
A：____
B：For two days．
B：At Green Store。
B：It's six dollars．
B：I've given it to Peter．
B：Because he likes it a lot．
A．How much is it?
B．Why did you give it to Peter?
C．How long have you had it?
D．Where did you buy it?
E．Why are you selling it?
F．Where's your old model plane?
G．Can I have a look at your old model plane?
