why has this proved difficult
新概念二册52课将答案用括号的词连起.Why has this proved difficult?Do they cov
This medicine has proved effective.中的proved为何是连系动词?
A fact is sth that can be proeved This has proved to be corr
it has proved or it has been proved
why has the team struggled this year?
选哪个,请给出原因.A.proving B.proved C.was proved D.has been proved
many a successful story has proved it.
It has been proved that qats will.
the operation proved to be very difficult.it proved to be __
The search proved difficult,为什么不是The search was proved diffi
The search proved difficult和The search proved to be difficul
The search proved difficult.这句话为什么不用被动语态