The second conditional is used to talk about things which are unreal (not true or not possible) in the present or the future -- things which don't or won't happen 

The past perfect, also called the pluperfect, is a verb tense used to talk about something that happened before something else that is also in the past.  

Do you know the difference between the present perfect tense and the present perfect progressive (continuous) tense in English? Learn how and when to use these tricky verb tenses. This video includes a practice exercise at the end so you can see what you've learned. Happy studying! 

Learn all about the past progressive verb tense in this Ellii grammar video! Our clear explanation will help you understand when and why to use this tense in no time. The difference between the past progressive and the simple past is also covered.