A、 The increase in beachfront property value.
B、 An experimental engineering project.
C、 The erosion of coastal areas
D、 How to build seawalls.

【正确答案】 C

【答案解析】解析：主旨题。根据…the topic that should be of real concern to civil engineers：the erosion of the US beaches．可知主要讨论的是美国沙滩的侵蚀问题。因此，正确答案为C。

A、 To protect beachfront property.
B、 To reduce the traffic on beach roads.
C、 To provide privacy for homeowners.
D、 To define property limits.

【正确答案】 A

【答案解析】解析：细节题。根据Some way communities have tried to protect their building and roads and to build seawalls．可知建造海堤的为了保护海滨资产，如楼房和道路。因此，正确答案为A。

A、 By sending water directly back to sea with great force.
B、 By reducing wave energy.
C、 By reducing beach width.
D、 By stabilizing beachfront construction.

【正确答案】 B

【答案解析】解析：细节题。根据If the flow of the beaches is gentle，the water energy is lessened as it washes up along theshore．可知稍微倾斜的海滩能减少水能，以此来防止侵蚀。因此，正确答案为B。

A、 Protect roads along the shore.
B、 Build on beaches with seawalls.
C、 Add sand to beaches with seawalls.
D、 Stop building seawalls.

【正确答案】 D

【答案解析】解析：细节题。根据Because of the real risk of losing beaches，many geologists support a ban on all types of stabilizing construction on the shore lines．可知发言者可能建议工程师停止建造海堤。因此，正确答案为D。