Thirteen new compounds of the alkyl styryl indoline spirobenzopyrans were synthesized from the condensation of 2-methylene indoline with the designed salicylaldehyde.
Approximately thirteen seconds before impact, the Copperhead's laser light sensor becomes active, and it uses fins to guide itself to the laser light source.
In chapter thirteen, Aristotle outlines an ideal of the central character of tragedy, the so-called tragic hero, and identifies the source of the character's downfall with something called hamartia.
（汇总） 
13
。
利的数字。
地前大约13秒时铜斑蛇的激光传感器启动，利用直尾翅制导攻击激光照射目标。
月， 而立法运动举步维艰。
听写训练
和13
十五。你孩子来过夜？
