1 arm

2 helper

1 arm

1 to miss narrowly

2 to let a great opportunity slip

1 crook of the arm

1 arm

1 lit. to have three heads and six arms (idiom)

2 fig. to possess remarkable abilities

3 a being of formidable powers

1 to lend a helping hand (idiom)

1 as the arm moves the finger (idiom)

2 freely and effortlessly

3 to have perfect command of

1 to issue a call for action

2 to raise one's hand and issue a rousing call (idiom)

1 a mantis trying to stop a chariot (idiom)

2 to overrate oneself and attempt sth impossible

3 also written 螳臂擋車|螳臂挡车[táng bì dǎng chē]