未知题型 Only those who can to lose their money should make high-riskinvestments.　　A) afford B) endure C) sustain D) maintain

未知题型 Science and technology have ___ in important ways to the improvement of agricultural production.A) attached B) assisted C) contributed D) witnessed

未知题型 There has been a collision ___ a number of cars on the main road to town.A) composing B) consisting C) involving D)engaging