________ many times, he finally understood it.
He is a man with rich experience , from ______much can be learned . A whom B which C whereD what
There was _____to prevent the accident . A something could doB anything we could do C nothing we couldn’t doD nothing we could do
---- Is Mary coming to the concert? ---- I think ________.
---- Have you been here long? ---- _______.
________ mud on his trousers brushes off easily.