.......Saturday morning
A: at
B: no preposition
C: on
D: in
.... twelve o´clock
A: in
B: on
C: at
D: no preposition
... the evening
A: in
B: at
C: no preposition
D: on
...... this evening
A: at
B: on
C: no preposition
D: in
...... Christmas
A: in
B: no preposition
C: at
D: on
.... yesterday
A: at
B: no preposition
C: on
D: in
..... the future
A: no preposition
B: at
C: in
D: on
...... summer
A: in
B: no preposition
C: on
D: at
..... last summer
A: no preposition
B: in
C: at
D: on
..... my birthday
A: on
B: no preposition
C: in
D: at
.... midnight
A: in
B: at
C: no preposition
D: on
..... New Year´s Day
A: no preposition
B: in
C: on
D: at
.... 1918
A: at
B: in
C: no preposition
D: on
..... the nineties
A: on
B: at
C: in
D: no preposition
.... the nineteenth of March
A: on
B: no preposition
C: in
D: at