Mrs. Taylor's class - It's Been Fun!
by Ron Sweet

Answers in gray have no clues; they must be deduced from the crossing letters.  When filled in correctly, the entries reveal a four-word phrase that conveys my wish for you.

Mrs. Taylor's class - It's Been Fun! grid

Across
1Quite an extraordinary thing from the past (7)
8Soda I spilled; goodbye, amigo! (5)
12Tilt with very little fat (4)
13Small? Large? I'm skinny! (4)
14We hear you make a sweater, perhaps, for standard of measurement (4)
16The boy's greetings (3)
17Mister E. openly displays music system (6)
19Finally say the words “positive response” (3)
21Request a small kitten, at first (3)
24Rodent, swallowing BB and trace of iron, is one who hops? (6)
25Okay to hug a tree (3)
27The smallest possible amount of an element from sources of all types of metals (4)
28Soft drink company, Los Angeles (4)
29Not good, with leopard initially having no hair (4)
30Normal behavior, to start with; hungry one took a nibble (5)
31They have eyes, and require half of lesson (7)
Down
1European mountain expression of surprise for first of the Greeks? (5)
2Rather recent Nebraska desire (6)
3Sat back, holding good price indicators (4)
4To the listener, quote a predetermined amount (5)
5We do turn crazily in current running out to sea (8)
6Badly garble a branch of mathematics (7)
7Like Toby, confused quantity of computer memory (8)
9Get out of the way of bird (4)
10Very dark in Kentucky (4)
11Ty's messy pigpen (3)
13Writes hastily, finally trips and walks on hands and knees (7)
15Snoopy, for example, starting to become a symbol of America (6)
18Female relative is friendly, showing trace of enthusiasm (5)
20Slides with small children (5)
22Check no bags containing door opener (4)
23Half a truck? (4)
25Like some tests, or a final, at last (4)
26Scrooge's expression starts to bother another helper (3)

Solution