| I | quack |
|---|---|
| you | quack |
| he/she/it | quacks |
| we | quack |
| you | quack |
| they | quack |
| I | quacked |
|---|---|
| you | quacked |
| he/she/it | quacked |
| we | quacked |
| you | quacked |
| they | quacked |
| I | have | quacked |
|---|---|---|
| you | have | quacked |
| he/she/it | has | quacked |
| we | have | quacked |
| you | have | quacked |
| they | have | quacked |
| I | had | quacked |
|---|---|---|
| you | had | quacked |
| he/she/it | had | quacked |
| we | had | quacked |
| you | had | quacked |
| they | had | quacked |
单语范例（未经PONS编辑处理）
They were widely used in x-ray machines, spark-gap radio transmitters, arc lighting and quack medical electrotherapy devices from the 1880s to the 1920s.
en.wikipedia.org The call is a series of quack or wok sounds that may last for up to two minutes.
en.wikipedia.org Leo has been portrayed as a classic quack, doing and saying very weird things.
en.wikipedia.org And it seems to me that you are no better than the so-called marvel-mongers, nay not even than the rest of the quacks and sophists.
en.wikipedia.org The answer is quack because saying a word with a letter k in it forces you to smile.
en.wikipedia.org