利用（）起爆炸药既不方便也不安全。
A、热能
B、机械能
C、爆炸能
参考答案：B
伤寒第一次菌血症（）。
A.潜伏期
B.初期
C.极期
D.缓解期
E.恢复期
All people, ________ they are old or young, rich or poor, have been trying their best to help those in
need since the disaster.[ ]
A. even if
B. whether
C. no matter
D. however
