e.g.          for example <              less than
≤            no more than
>              more than
≥            no less than
≈            approximately
=              equal to
≠            not equal to
*               important
**             very important
×            wrong, bad
√            right, good
↑            increase
↓            decrease
+             better
－            worse
∵            because
∴            so
←            reason
→            result
?              question
!               key point
∈            belong to
&             and
缩写:
cont.        for continued
ed            education
Prof.         professer
ch            child
curr          curriculum
chem       chemistry
hist           history


c/room     classroom
geog        geography
Lng          learning
bk            book
prob         probably
ex             exercise
with           w/
18th century         18c