氧气瓶夏季防晒，冬季应防冻严禁用（）直接加热解冻，只准用（）解冻。
参考答案：明火；热水或蒸气
Keep your confidence up by taking gradual steps forwards, rather than freezing, when ______ with what
seems like great trouble.
A. to face
B. face
C. facing
D. faced
整合
