中式酯易溶于()中。 ["硫酸","水","苯族烃"]
下述属于飞机二次电源的设备有:() ["A、IDG","B、APU GEN","C、SI","D、BAT/RAT或HDG"]
中式酯可溶于()中。 ["苯类油","稀硫酸","水","氨水"]
个体生理发育对心理发展的影响主要表现在()的成熟对心理发展的影。 ["神经系统和内分泌系统","性器官和神经系统","性器官和内分泌系统","神经系统和身体发育状况"]
根据《城镇燃气设计规范》,室内压缩天然气管道宜采用()。(条款7.5.6) ["管沟敷设","直埋铺设","架空敷设","套管敷设"]
AM信号的波形和频谱有哪些特点?