问题
选择题
When you _____ a word in a dictionary, firstly you should look at the first letter of theword. [ ]
A. look up
B. look for
C. look at
D. look over
答案
答案：A
搜题请搜索小程序“爱下问搜题”
When you _____ a word in a dictionary, firstly you should look at the first letter of theword. [ ]
A. look up
B. look for
C. look at
D. look over
答案：A
已知X、Y、Z、W均为中学化学中常见的单质或化合物，它们之间的转化关系如图所示(部分产物已略去)。则W、X不可能是( )。
| 选项 | A | B | C | D |
| X | C | Fe | Ca(O H)2溶液 | AlC3 |
| W | O2 | HN3 | CO2 | NH3·H2O |