loading23．C推理判断题。根据倒数第二段中的…it will freeze around the popsicle stick和最后一段的第一句…wan a few minutes for your popsicle to harden可知，等几分钟果汁就会变硬，变成棒冰，说明干冰的作用是使果汁结冻。 13.
14.29-31 ACB
15.25-28 CDDC
16.21-24 CABD 17.
32--35 BCAC 18.
27--31 CBCDA 19. 24-26 ADB 20. 21-23 DAC 21. 32-34. CBA 22.
28-31. DDA A 23.
24-27. CBCA 24. 21-23DAC
25.32-35 ADDB
32-35 BAAC
26.28-31 DADC
27.24-27 BAAD
28.21-23 CAD