根据汉语提示完成句子。

1．我上学期学习数学有困难.

      I had___     ___     math last term.

2．他不知道怎样使发音正确.

      He doesn't know how to get the___     ___     ．

3．练习对话一定会帮助你提高口语能力.

      Practicing conversations must____  your ___     ___     .

4．他们发现大声朗读很有用.

      They find ____   very useful ___     ___     ___     ．

5．他不害怕面临挑战.

      He is not ___     ___     ___     the challenge.