think /θɪŋk/ , thought /θɔːt/ , thought /θɔːt/
The French translation is penser, or réflechir (songer à), sometimes croire, see below.
Note the presence of the resumptive pronoun so:
- Will we back to work on April 15th
- I (don't) think so. (Je (ne) crois (pas).)
You know something or you don't, but thinking is an activity, so it is compatible (and frequently used) with -ing Descartes' famous "Cogito ergo sum" is therefore precious nonsense.