The air is deadly polluted because some factories don't ________ the rules to protect the environment.
You are required to write _______ so that we can see it clearly.
---When shall we meet again ? ---Make it ______ day you like; it’s all the same to me.
Last year the well-known actress did _______ she ________ help the poor children in the mountain village.
In order to prevent the fire spreading, some of the houses nearby had been ________ before firemen arrived.
Peter hurried through dinner, changed into old clothes, _______ in the lab for three hours.