要解决废弃塑料带来的“白色污染”问题，应该采取的两条措施是_________、___________。
使用可降解塑料 ；减少使用塑料制品
The newcomer went to the library the other day and searched for ________ he could find about
Mark Twain. [ ]
A. wherever
B. however
C. whatever
D. whichever
主要炼焦煤种有气煤、肥煤、焦煤和（）。
