Predicate 
decelerate:
  Frames file for 'decelerate' based on sentences in wsj.  Verbnet
  entry 45.4.
Roleset decelerate.01 Verbnet Class: 1 "(cause to) slow down":
Roles:
Arg0:agent, causer of slowing
Arg1:entity slowing down
Examples:
| unaccusative (-) | 
|---|
person: ns
tense: present
aspect: perfect
voice: active
form: participle
| He argued that both CPI and PPI have in fact decelerated since spring.
 
 | 
| Arg1: | both CPI and PPI | 
| ArgM-DIS: | in fact | 
| REL: | decelerated | 
| ArgM-TMP: | since spring | 
| agentive (-) | 
|---|
person: ns
tense: past
aspect: ns
voice: active
form: full
| John decelerated the car.
 
 | 
| Arg0: | John | 
| REL: | decelerated | 
| Arg1: | the car | 
Unaccusative will be more common, methinks.