They _ (investigate) the causes of gas explosion since last

They _ (investigate) the causes of gas explosion since last the spark ignites a can of gas and causes a rapid expansion Explosion of the heaven will come soon.They appear with grea Explosion in Japanese Reactor causes fear of meltdown,求标题翻译, They failed _ (get) to the top of the hill at last. The spark causes a small explosion in the engine .怎么翻译 the tragic causes of Tess since the last of last year与什么时态连用 in the ear of knowledge explosion 英语翻译To investigate the state of environmental accounting pra since the end of last years用什么时态 The price of eggs _____ by 10％ since last month.