根据所给的句子以及汉语释义，用所学过的单词或短语完成句子，每空一词。
小题1:________ ________ ________(直到现在)，we have finished Book 4.
小题2:We are not allowed to ________ ________(参考)our notes in the exam.
小题3:His laziness can perfectly ________ ________(为…做出解释) his failure.
小题4:No one knows exactly how the fire ________ ________（爆发）last night.
小题5:Women are still being ________ ________ ________（看不起）in some areas.
小题6: It was hard for him to ________ ________ (挑出)his teacher in the crowd.
小题7:Keep on working like this and you will succeed ________ ________(迟早).
小题8: ________ ________ ________ I know (据我所知)，he is from America.
小题9:They ________ ________ ________(屏住呼吸) and watched the cat closely.
小题10:With so many animals ________ ________(灭绝)，the environment is becoming worse and worse.