一维流动的连续性方程υA=C成立的必要条件是______。 A理想流体；B黏性流体；C可压缩流体；D不可压缩流体。

We very much () that you are not in a position to entertain any fresh orders at present.

A、regret

B、regret to learn

C、regretful

D、regrettable

Dear Sirs,

We were very surprised to learn from your call today that one of the books you ordered was damaged. We called our warehouse manager this afternoon and he confirmed that a new replacement will be delivered to you by DHL by tomorrow (147) the latest.

We truly regret the damaged delivery and the inconvenience it (148) you.

We have (149) taken the matter up with DHL and are sure that this will not happen again not only to you, but also to all our cherished readers.

Meanwhile, may we suggest that you trust us again and do business with us continuously.

(47)

A．at

B．to

C．for

D．in

A．out of stock .

B．in stock

C．on stock

D．no stock

A、Despite

B、Since

C、While

A．meet

B．agree

C．supply

D．stipulate

We do not mean to be disrespectful when we refuse to follow the advice of our leader.

A．venerable

B．respectful

C．famous

D．gracious

We feel sorry but we have to inform you that the materials you ordered are out of stock. (regret)

A、accepting

B、entertain

C、receiving

D、take