Letter Equation Riddles

These riddles involve identifying an original phrase whose letters have largely been replaced with their first letter.
For example, 3 B Ms (S H T R) may be 3 Blind Mice (See How They Run).
Plurals should be marked with an 's' even if absent from their plural form, as with Ms and Mice.

0 D 30
1 R to R T A
2 Ps in a P
3 Hs on a C (with a S H)
4 Fs on 1 H (E Y T)
5 Es: E, A, F, W and A
6 G a-L (in the 12 D of C)
7 Cs of the R
8 S on a S S
9 L (but O I Y a C)
10, X in R N
11, the A N of S (NA)
12 M Ns (A, A-S, B, C, C-S, D, D-S, E, F, F-S, G, G-S)
13 is Y A at the E of Y F Y of HS
14 Es of F (before it was C)
15 Ms in a Q of an H
16 Ps in a C S
17 Ss in a G (and 29 Ks in a S)
18, the G of the N Gs (on the P T)
I W O 19 (a S about the V W)
20 S on a D B
21, the L D A (in the U S)
28 Ds in F, B...
29 Ds in F in a L Y
40 Rs to S in this P
42, the M of L, the U and E
54 Ss on a R's C
69 L L G (the S of the Z), when V S
100 Ds C (the T at W W Bs)
195 Cs (I the H S and the S of P)
300 S (at the B of T)
896 T P in R & G, G & S, R & S, D & P, B & W, X & Y, S & M and S & S.
1789, the B of the F R
2033, the PC of K
20000 Ls U the S
525600 M (H D Y M? M a Y?)
1000000 Ds, the A of M D by D. E
8675309/J (by T T)
299792458 M/S, the S of L
01189998819991197253, an E N that's E to R (from the IT C)