* I brought you a big box so that you might/can pack your books in it. * They like the way she plays with them.

The intentions of the sentences come across clearly, but there are some minor errors. "Let's wait a little. He will probably come." → This sentence makes sense. "I brought you a big box so that you might packed your books in." → I understand what you're trying to say, but it would be better phrased as: "I brought you a big box so that you can pack your books in it." "I gave him several injections." → This makes sense. "It’ll be easy for her to make friends with the children. They like the way she playing with them." → This would be better phrased as: "It'll be easy for her to make friends with the children. They like the way she plays with them."