In aquariums it takes several months for the various bacteria to develop a food web and to establish themselves in the gravel of the start-up tank.是什么意思_In aquariums it takes several months for the various bacteria to develop a food web and to establish themselves in the gravel of the start-up tank.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句