A:x+1
B:x﹣1
C:1﹣x
D:﹣x﹣1
I brush my teeth and wash my face. ____
I go to school.____
What do you do after breakfast? ____
I go to school on foot. ____
What do you do before breakfast? ____
How do you go to school? ____
根据拼音写汉字。
wǎn
shè
fèi
tuō
qū
yí
____ 言谢绝
用激光测距仪测量两座山峰之间的距离,从一座山峰发出的激光经过4×10-5秒到达另一座山峰,已知光速为3×108米/秒,则两座山峰之间的距离用科学记数法表示为( )