How to indicate plurality/singularity
You can also use 好 to emphasize many:


  我有好几个朋友 Wǒ yǒu hǎojǐ gè péngyǒu - I have lots of friends
  
  好多人来看我 Hǎoduō rén lái kàn wǒ - Many people came to see me


In this case the 好 is strongly emphasized.

好几个 = Lots

好多 = Very many



To suggest some or a few:


  我有几个朋友来看我 Wǒ yǒu jǐ gè péngyǒu lái kàn wǒ - I have some friends coming to see me
  
  有一些同学跟我一起去看电影 Yǒu yīxiē tóngxué gēn wǒ yīqǐ qù kàn diànyǐng - Some of my classmates will go with me to watch a movie


几个 = Some

一些 = A few



To emphasize singularity:


  我只有一个朋友 Wǒ zhǐyǒu yīgè péngyǒu - I only have one friend 
  
  你是唯一来看我的人 Nǐ shì wéi yī lái kàn wǒ de rén  - You are the only person to come
  and see me


只有 = Only have

唯一的 = The only one