1. allow sb. to do sth. 允许某人做某事(主动语态)如：
mother allows me to watch tv every night. 妈妈允许我每晚看电视。
be allowed to do sth. 被允许做某事(被动语态)如：
lily is allowed to go to qinzhou. 莉莉被允许去钦州。
2. get their ears pierced 穿耳洞
让/使(别人)做某事 get sth. done(过去分词)
have sth. done 如：
i get my car made. == i have my car made. 我让别人修好我的车
3. enough 足够
形容词 enough 如：beautiful enough 足够漂亮
enough 名词 如：enough food 足够食物
enough to 足够…去做… 如：
i have enough money to go to beijing. 我有足够的钱去北京。
she is old enough to go to school.她够大去读书了。
4. stop doing sth. 停止做某事 please stop speaking.请停止说话。
stop to do sth. 停止下来去做某事 please stop to speak.
5. 看起来好像…sb. seem to do sth. he seems to feel very sad.
it seems that 从句it seems that he feels very sad. 他看起来好像很伤心。
6. 系动词不能独立作谓语，要和表语一起构成谓语。常用的连系动词有：look, feel, be, become, get, turn, smell, taste, stay(保持), kept等。连系动词除be 和become 等少数词可接名词作表语外，一般都是接形容词。 如：
they are very happy. he became a doctor two years ago.
she felt very tired.