Compound surfaces are more difficult and expensive to fabricate.
复合的表面在制造上更困难,花费也更大。
2
Pinpointing exactly which compounds have an effect is difficult, lots of blood is needed to be able to single out and test enough of each compound found.
困难的是明确哪种化合物有效,需要筛选大量血液,并对找到的每个化合物进行充分测试。
3
Once the program is working, you might want to remove some of the scaffolding or consolidate multiple statements into compound expressions, but only if it does not make the program difficult to read.