add, add to, add...to, add up to
都是add的固定搭配词组。
add: 作“加，增加”解时，既可作及物动词，又可用作不及物动词；作“又说，补充说”解时，与直接或间接引语连用。
- if the tea is too strong, add some more hot water.
如果茶太浓了，再加点开水。 - after a short while, he added that he would try his best.
过了一会儿，他又接着说他会尽力。
add to: 意为“增添，增加，增进”。
- the bad weather added to our difficulties．
恶劣的天气增加了我们的困难。
add...to: 意为“把......加到......”，是把前一项加到后一项之后或之中。
- add two to seven, and you will get nine.
七加二等于九。
add up to: 意为“加起来总共是／累计得”，该短语不用于被动语态。
- all his school education added up to no more than one year.
他的学校教育加起来不过一年。
