Yossi asked this question last year. I promised to get around
to it. So this year on Lech Lecha he asked again. The question
sheds interesting light on Rashis use of language

SUCCINCT SUMMARY
----------------
In this posting Rashi explains grammatical rules. In Hebrew,
by affixing a Hebrew letter hey at the end of a word we
change the meaning as follows:(A) If the word is the name of
a place then the word + HEY means TO THAT PLACE. (B) If the
word is a verb then the word+HEY means I WOULD LIKE TO DO SUCH
AND SUCH. (Grammarians have fancy names for this transformation)

Rashi also explains rules of conjugation. Every Hebrew root
can be conjugated in one of 7 grammatical modes. Rashi points
out that the PIEL mode can refer to NEGATION.

EXAMPLE 1 Gn32-04b
------------------
Jacob sent angels to Esauv, TO Edom (EdomHEY)

EXAMPLE 2 Gn33-12a
------------------
And Esauv said I WOULD LIKE to journey with you (NSA + HEY)

EXAMPLE 3 Gn32-26b
------------------
The Hebrew root T-K-A refers to posting a tent.
In the PIEL mode T-K-A refers to UPROOTING (unposting)
Hence the verse: Jacobs knee cap was DISLODGED

List of words/roots with HEY indicating TOWARDS or DESIRE

List of roots with       PIEL denoting negation

SUCCINCT SUMMARY
----------------
A powerful Rashi technique is the ALIGNMENT method in which
almost similar verses are aligned. The minor differences
between them sheds light on nuances and details. An equally
powerful use of alignment is to infer meaning of unknown terms

EXAMPLE 1,2 Gn32-16a Gn32-16b
-----------------------------
In Gn32-15:17 we see listed 5 types of animals
- she goats----------------he-goats
- ewes---------------------rams
- camels-------------------children
- cows---------------------bulls
- she-donkeys--------------he-donkeys

Notice how every pair is FEMALE-MALE except for the camels.
Rashi infers the nuance that camels are modest in their
marital relationship and hence the Bible didnt explicitly
mention male camels.

From the five fold alignment of female-male pairs we infer
the meaning of the last mentioned animal--it MUST mean
he-donkeys.

Note the simplicity with which Rashi makes his inferences

EXAMPLE 3 Gn33-07a
------------------
Similarly in Gn33-06:07 we have listed the following pairs
- The maids---------------and their children
- Leah--------------------and her children
- Joseph------------------and his mother Rachel

Notice the reversal in the last Row--the child is mentioned
prior to the mother. Rashi again infers a nuance of modesty.
Joseph was worried how uncle Esauv would react to his
beautiful mother so he stood in front of her so he shouldnt
get aroused.

EXAMPLE 4 Gn32-10a
------------------
Jacob refers to God in this verse as
- Lord of Abraham
- Lord of Isaac
- God
Rashi aligns the names of God in these verses
with the names of God in other verses to show
that Jacob hinted at two promises of safety from God

Gn28-13:15 I am LORD OF ABRAHAM, LORD OF ISAAC: I will watch you
Gn31-03    I GOD will be with you

List of verse*1 with       5 pairs of male-female animals

List of verses*1 with      3 pairs of mothers-children

List of verses with      Names of God - promises of safety*1

List of verse*1 with       5 pairs of male-female animals