看图填出哺乳动物心脏的结构及与其相连的血管
①、____ ②、____
③、____ ④、____
⑤、____ ⑥、____
⑦、____ ⑧、____
⑨、____ ⑩、____ .
Hello! I'm Sally. I'm an English girl. Now I'm in Beijing with1parents. Today is Sunday. I2to Yangguang Clothes Store. Wow! I see lots of3clothes in it. They have sweaters at a good4. They have some bags5sports. They have hats in red, black6yellow. The white7are on sale. They8only 15 dollars. I think they are cheap(便宜的), so I9a small one for myself and a large one for my10.
关于自立,下列说法错误的是( )
下列物质中既能跟稀H2SO4反应,又能跟氢氧化钠溶液反应的是( )
①NaHCO3 ②Al2O3 ③Al(OH)3 ④Al ⑤Na2CO3.
观测日食不能用肉眼直接对着太阳,如果没有专用的太阳滤镜,可采用如图所示的简便方法:一是准备一盆黑墨水置于阳光下,在脸盆中观察太阳的像,这是利用____成像原理;二是将手指展开互相垂直叠放,只留有小缝隙,对着阳光,在白纸上观察太阳的像,这是利用了____成像的原理.日食的形成可以用____来解释,此时太阳、地球、月球正好在同一直线上,处在中间位置的是____.