Php SQL试图插入到数据库中

PHP不断抛出一个错误，告诉我有语法问题，但没有提供其他信息，这是怎么回事

$sql = "INSERT INTO objective_form (name, doa, dob, pmuscle_length, palpation, accessory_movements, functional_tests, myotomes, dermatiomes, refles, ntpt, special_tests, working_hypothesis, plan, tx)
 VALUES ('$name', '$doa', '$dob', '$pmuscle_length', '$palpation', '$accessory_movements', '$functional_tests', '$myotomes', '$dermatiomes', '$refles', '$ntpt', '$special_tests, 
 '$working_hypothesis', '$plan', '$tx')";
if(mysqli_query($link, $sql)){
    echo "Recorded successfully.";
} else{
    echo "ERROR: Could not able to execute $sql. " . mysqli_error($link);
}    

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在值行中的$special_测试之后，您忘记了撇号（'）。尝试：

$sql = "INSERT INTO objective_form (name, doa, dob, pmuscle_length, palpation, accessory_movements, functional_tests, myotomes, dermatiomes, refles, ntpt, special_tests, working_hypothesis, plan, tx)
 VALUES ('$name', '$doa', '$dob', '$pmuscle_length', '$palpation', '$accessory_movements', '$functional_tests', '$myotomes', '$dermatiomes', '$refles', '$ntpt', '$special_tests', 
 '$working_hypothesis', '$plan', '$tx')";

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如果这仍然不起作用，请执行

echo$sql

并尝试在sql本身中运行该命令，这将显示语法错误的位置。

能否显示确切的错误消息？如果执行“echo$sql”并尝试在sql中运行代码，会发生什么？