A level gauge for a tank is to （）.

Because the circulating water is in a closed loop,_______is installed to cater for expansion and contraction of the water at different conditions of operation. A.an expansion joint B.a drain tank C.a head tank D.a contraction tank

class Tank { int level; } public class TestTank { public static void main(String[] args) { Tank t1 = new Tank(); Tank t2 = new Tank(); t1.level = 9; t2.level = 47; System.out.println("1: t1.level: " + t1.level + ", t2.level: " + t2.level); t1 = t2; System.out.println("2: t1.level: " + t1.level + ", t2.level: " + t2.level); t1.level = 27; System.out.println("3: t1.level: " + t1.level + ", t2.level: " + t2.level); } }‍‎

class Tank { int level; } public class TestTank { public static void main(String[] args) { Tank t1 = new Tank(); Tank t2 = new Tank(); t1.level = 9; t2.level = 47; System.out.println("1: t1.level: " + t1.level + ", t2.level: " + t2.level); t1 = t2; System.out.println("2: t1.level: " + t1.level + ", t2.level: " + t2.level); t1.level = 27; System.out.println("3: t1.level: " + t1.level + ", t2.level: " + t2.level); } }

For large two-stroke diesel engine, the lubricating oil required for cross head bearing lubrication comes from the_____. A: settling tank B: lubricating oil circulation tank C: Wet sump D: Daily service tank

The amount of lubricating oil in the drain tank should be checked by （）.

Expansion tank (see Fig.3-13) is used to fill the coolant．

Which of the following operation is correct?______. A: After being treated in the bio-filter tank, the sewage is discharged overboard B: After going through the biological film, the sewage is discharged overboard C: The sewage treated in the bio-filter tank flows into the sterilization compartment D: The sewage is first collected in sterilization tank then discharged into the bio-filter tank.

It takes ______ to produce the first tank top by using 3D printer.

Frames to which the tank top and bottom shell are fastened are called（）.