[单选] why should the SES operators be very careful when the ship enters the area where three ocean regions overlap? Because（）.
A . the weather over there is always terrible B . the condition there is complicated C . the signals are too strong D . their SES may receive the signals from unwanted satellite
力学性能中最主要和最基本的指标是什么？
装置内火炬的设备应满足哪些要求？
简述梅毒的报告要求。
The quality of EGC messages is（）affected by the position of the ship, the time of reception and climatic conditions. sometimes。 all times。 never。 partly。
预应力钢筋包括哪些？
why should the SES operators be very careful when the ship enters the area where three ocean regions overlap? Because（）.
