Lesson 50 provides examples of two sentences that describe to activities (one occurs before, while or after the other). The Hebrew word "CaaSher" is the equivalent of while. "CaaSher" can be replaced with "Csheh" "Csheh" however, is not an independent word rather it is a prefix and is attached to the word that follows it.
Following "Lifney" (before) and "Acharey" (after) a linking "Sheh" as a prefix to the word that follows it is required. The "Sheh" is used before a clause that describes time but is not used before a noun that does the same. To translate the sentence I went home after the party there is no "Sheh" following "After". To translate the sentence I went home after I danced at the party "Sheh" must be following "After".
Also, both verbs have to be in the same tense. In Hebrew people cannot say:"I went home after I dancing at the party".
Translation of text in page 150
Before people started to use the Alef-Beit letters, they drew on stones, walls and processed "Papyrus" bushes.
For example, they drew a foot, or a hand or an eye or a head. They drew only things the saw. because they did not know how to draw thoughts.
The Alef-Beit was not born in one day. Researchers do not know where and when exactly, did (people) start using the A_B. The archaeologists who examined old inscriptions, think that the history of the A-B starts with the scripture of the (Phoenicians) a nation that lived in Tyre and Sydon (Lebanon) 3,000 years ago.
In the Phoenicians A-B each letter was a drawing of something that started in this letter. I.e. the letter A was a drawing of a bull, because the word bull, in Phoenician started with the letter A. Or the letter B was the drawing of a house, since the word House in Phoenician starts with a B. The Israelites got the Phoenician A-B and wrote Hebrew in Phoenician letters. In the GeZer Calendar from 1000 B.C. we can see read Hebrew words in Phoenician letters.
Also the Aramaic people got the Phoenician A-B and wrote Aramaic in Phoenician letters. From this scripture "were born" both the Arabic scripture and today Hebrew scripture. Also the Greeks took the Phoenician A-B and later the Romans learned it from the Greeks and that is how the Latin Scripture "was born".