"The woman sees the child."
Translation:Die Frau sieht das Kind.
There is a table for conjugating regular verbs on Basics 1's Tips tab. It can be found to the left of the discussions tab, right below the 4 lessons of Basics 1. (http://duolingo.com/#/skill/de/Basics-1)
Most German verbs are regular and the irregular verbs will need to be memorized. Though most of the irregular verbs do follow a pattern so you do not necessarily have to memorize every single conjugation. (http://german.about.com/library/anfang/blanfang04b.htm)
You can also Google "German conjugation present tense to [verb]" to check the conjugation of a specific verb.
'child' is the direct object here (the one being seen) so we use the accusative case
Use "seht" when the subject is second person plural (you guys, you all). Ihr seht.
Use "sieht" when the subject is third person singular (he, she, it). Er/sie/es sieht.