But for your timely warning, we ___have been unaware of the danger. Thank you very much!
There have been so many school bus accidents recently.________,people are concerned about the school bus safety much.
________children get older,they become more and more interested in the things around them.
Someone called me up in the middle of the night, but he hung up __ I could answer the phone.
— Why do you look sad? — There are so many problems _____.
There’s no doubt ________ international cooperation is the key to ______ with cybercrime.(网络犯罪)