树脂的圆球率，正常情况下应达到（）以上。
A、50％
B、60％
C、80％
D、90％
参考答案：D
根据图片提示完成下列句子。
1. —Where's your pen pal from?—He is from _______.
2. Does his aunt go to _______?
3. Where can you see the sightseeing in the picture?_______ in China.
4. If you visit _______, you can see Tian'an men Square.
5. Look at the flag, Which _______ is it? It is United States.
将下列空格里填上适当概念的序号：①物理变化 ②化学变化 ③物理性质 ④化学性质
硫是一种淡黄色固体______，把块状硫研成粉末，将少量硫粉放在燃烧匙中加热，硫慢慢熔化______，继续加热，硫开始燃烧______，产生微弱的淡蓝色火焰，生成的气体无色具有刺激性气味，这说明硫具有可燃性______．
1. —Where's your pen pal from?—He is from _______. 
2. Does his aunt go to _______? 
3. Where can you see the sightseeing in the picture?_______ in China. 
4. If you visit _______, you can see Tian'an men Square. 
5. Look at the flag, Which _______ is it? It is United States.