請幫忙看一下動詞和文法是否正確~

請幫忙看一下以下的文法是否正確? 感謝
括弧內提供詞語. 括弧前是答案

Dear Mr Johnson,

We have received (receive) your letter dated 18 June and that is (be) to you for lending (lend) us such a great support. I believe that the property market in the mainland is promising (promise) and trust that both of us will benefit (benefit) from this new venture in the long term although the preparatory works already cost (cost) over a billion dollars.

Please kindly note that my assistant, Mrs. Terry Brown appointed (appointed) to take up the venture for me for the time being as I am getting (get) another urgent project in hand now. Mrs. Brown has been working (work) with me for more than ten years. She is reliable and competent, and she is ready to render you assistance at anytime. She can be reached (reach) at 2430 1211 during office hours. Please advise (advise) her your request whenever needed.

Please also note that the design of the construction had been changed (change) slightly as marking (mark) in the enclosed (enclose) drawing. We would be (be) glad if you could let us know whether the amendments are acceptable to you or not. I didn’t mention (not mention) it to you in our last meeting as it is not until this morning that I was informed (inform) of the change by our consultant. I am sorry for any inconveniences which had caused (cause) to you and look forward to receiving (receive) your views on the amended (amend) designs.

Yours sincerely,