Questions from 31 to 35 are based on the following passage:The exporter, as drawer of a draft (bill of exchange), hands the draft to his bank, the remitting bank, who in turn forwards it to the buyer through a collecting bank in the buyer’s country. A draft (also called a bill) is a written order to a bank or a customer to pay someone on demand or at a fixed time in the future a certain sum of money. If shipping documents accompany the draft, the collection is called “documentary collection.”Documentary collection falls into two major categories: one is documents against payment(D/P); the other, documents against acceptance (D/A).Documents against payment, as the term suggests, is that the collecting bank will only give the shipping documents representing the title to the goods on the condition that the buyer makes payment.Where the paying arrangement is D/A, the collecting bank will only give the buyer the shipping documents after buyer’s acceptance of the bill drawn on him, i.e. the buyer signs his name on the bill promising to pay the sum when it matures. In return he gets what he needs – the shipping documents.Under D/A, the seller gives up the title to the goods – shipping documents before he gets payment of the goods. Therefore, an exporter must think twice before he accepts such paying arrangement.

The meaning of D/A is（ ）.

A．documents against acceptance

B．documents against payment

C．delivery after payment

D．cash against payment

马拉硫磷是高效杀虫剂是因为（）

A.是高毒农药

B.人体对它的水解作用大于氧化作用

C.昆虫缺乏羧酸酯酶，无法水解

D.它是属于有机磷农药

E.以上说法都正确