If you want to say 'I want something', you can use 'hoshii'. ex) I want a camera. Watashi-wa kamera-ga hoshii. But If you want to say 'I want to do something', you can not use 'hoshii'. You should use '-tai' with verb. The root of the verb + tai. ex) miru(see) -> mi-tai(want to see), suru(do) -> shi-tai(want to do), iku(go) -> iki-tai(want to go) So your example becomes "Mi-tai dake desu(I just want to take a look at it)" "Mite dake desu" is not correct. It should be "Miru dake desu(I just take a look at it). Or the past form "Mita dake desu(I just took a look at it)" The particle "dake" follows an informal verb(miru, mita, suru, shita etc.), not -te form verb.