Although this won't be the last time that you learn about the particle mo も, this lesson will introduce you to its most important usages.
The adverbial particle mo も follows nouns to mean "also/too." Similarly to what happens when these two English words are used heavily in conversation, the particle mo も often helps soften the tone of a sentence.
This particle must never be used immediately after the particles ga が or wa は. Whenever it is after a noun that functions as a subject and/or topic, these particles are thought of as simply not being spoken. Usually, the particle mo もis not used after the particle wo either; however, you will see the combination “wo mo をも” in contexts such as older literature.
O-tenki mo ii desu ne.
The weather's good, too.
Boku mo onaka ga suita.
I too am hungry.
Tōkyō mo Kyōto mo ame desu.
There's rain in Tokyo and in Kyoto.
Seikō mo seikō, daiseikō da.
What a success, it was a great success.
Similarly to the contrastive wa は, the particle mo も may also emphasize sheer lack in negative sentences, or sheer intensity in positive sentences.
Ano kompyūtā wa goman’en mo kakaranai.
That computer doesn't even cost 50,000 yen.
Issenchi mo ugokanai.
To not move even a centimeter.
Gojikan mo matta.
I waited at least/about five hours.
Particle Note: In Ex. 7, mo も here implies perhaps a much longer wait, that is, you've already waited "at least five hours" and the wait has become unreasonable. This same logic can also explain Ex. 5. Here, it's implied that the cost of such a computer doesn't even exceed 50,000 yen. Since this equates roughly to $500, we can imagine that any much higher than that would be an exuberant price without the quality of the PC being far higher than standard expectations. In both cases, mo も is seen after some counter phrase.