光合产物是以哪种形式从叶绿体转移到细胞质中去的？（）。 核酮糖。 葡萄糖。 蔗糖。 磷酸丙糖。
Before welding in a tank that has carried petroleum products，the tank must be certified by （）. the Coast Guard。 the ABS。 the shipyard fire department。 a certified marine chemist。
为提高炼焦时焦饼的块度应适当增加（） 瘦煤。 气煤。 肥煤。
Before welding can be done in a tank that has carried petroleum products，a certificate must be obtained from（）. the customs。 the Register Bureau of shipping。 the shipyard fire department。 a certified gas chemist。
若谐振功率放大器原来工作在临界状态，只增加Vcc，其它电路参数不变，则放大器工作状态将如何变化？
In a （） boiler the water flows through the inside of the tubes while the hot gases pass around the outside.
