原式=-23a3b•9ab•18ab=-2398a3b=-23×34a2ab=-12a2ab.
Danny shops slowly, he is not _____________. [ ]
A. quickly
B. quick
C. loud
土壤中的硫以无机和有机两种形态存在,()。
A.0.09%
B.0.08%
C.0.05%
D.0.07%