Do you remember the buildingflew a red flag all the year round ?

Who do you suppose is the manour teacher is talking ?

Thank you for your help,we could not have finished the work in time.

The bikehe went to school was stolen last week,which made him feel sad.

He borrowed a book the other day ， the authoris a worker.

Mrs Zhang often tells us that spring is the timepeople go sight seeing.

Believe it or not,I dont like the wayhe spoke to me.

As is known to us all,the agechildren can go to school is seven.

相向掘进的巷道相距米时，必须停止一个头掘进。

瓦斯爆炸的三个条件是：一是浓度的瓦斯;二是温度为以上引爆火源;三是空气中氧浓度。